A/N: I was searching through my old stories and I found this, something I wrote when I was really into Danny Phantom. I looked through it and thought it was pretty good, though it is pretty old. Tell me what you think :3

But enough about that. I wrote this because I haven't seen any stories in which Jack finds out about Danny's secret. There's tons where Maddie figures it out/is told, but I haven't yet seen a one with Jack. So I wrote one. I hope it's good, and the characters aren't OOC :)

It was just after the Box Ghost had been sucked into the Fenton Thermos that Jack Fenton realized the evil ghost boy, Danny Phantom, was using his technology. He wondered how the ghost boy had gotten into his lab, and if the troublemaker had taken any of his precious fudge. If he had...

When Jack brought up the topic with Maddie, she told him Phantom probably came through the portal. But the ghost boy hadn't set of any alarms. In fact, the only time alarms had gone off in the lab was when Danny was wrongly (and strangely) accused of being a ghost. Maddie then suggested that he had forced a human to do it for him, but that wasn't likely either. The only humans in the lab were the Fentons, Sam and Tucker, and, every so often, Vlad, and they all knew that dealing with ghosts was a very bad idea. At least, he hoped they did.

That night, Jack set up surveillance cameras, focusing on a table where he had left a pile of Fenton Thermoses. The next morning, when Jack watched the tapes, he was very surprised: Danny, his own son, simply walked into the lab, calmly collected the Thermoses, and left. Jack was appalled; his son was helping the evil glob of ectoplasm! The boy didn't even appear to be overshadowed!

Later that day, Danny approached Jack and asked if he could go out. When Jack asked why, he said he was meeting his friends. He's going to see Phantom! Jack thought. Just has he was about to tell the boy he couldn't go, Jack was struck by an idea. If he followed his son, Danny would lead him to Phantom! Then he would tear the ghost boy apart molecule by molecule, in the name of science and the fudge Phantom may or may not have stolen/eaten! So Jack told Danny he could go, then followed him as silently as he could. To his surprise, Danny went to the Nasty Burger and sat down next to Sam and Tucker. When he heard Tucker ask if Danny'd gotten the Thermoses, Jack slid into a seat nearby and hid behind a menu to listen in.
"I got a bunch last night. There was a huge pile, just sitting there. It was so easy this time!" Danny was saying.
"Almost too easy..." Sam mused.
"Aw, c'mon, Sam. I deserve at least some good luck," Danny said, laughing.
"Sam's right, Danny," Tucker said worriedly. "Your dad might not be the sharpest knife in the drawer, but he's not stupid. He wouldn't just leave his inventions lying around where any old ghost could come and take them."
"Yeah," Sam said, happy Tucker was agreeing with her. "Your dad's bound to notice you've been using his inventions in your–" Sam broke off as Danny poked her in the arm, hard. At her indignant outburst of "WHAT?!", he gestured to where Jack was sitting. Oh well, he was never one for camouflage anyway.
Jack waved. "Hiya, Danny-boy!"
Danny groaned. "Dad, what are you doing here?" So he hadn't suspected Jack was eavesdropping on their conversation. Good.
"Oh, I just got a bit hungry," Jack said vaguely. Sam gave him a look, while Danny just shrugged and Tucker went to get the food. While they ate, the kids talked about normal stuff, like the school football team, the amount of homework they had gotten, and ghost hunting. Jack, realizing they probably wouldn't talk about Phantom while he was there, grabbed a burger and left.
Just as Jack reached the door, however, it flew open and revealed the Box Ghost (how he had escaped the Thermos so soon was beyond Jack). Unfortunately, Jack was low on weaponry at the time, so he backed away. To his surprise, Phantom appeared in front of him and sucked the Box Ghost into the Thermos just as the ghost was beginning his mantra.
The ghost boy turned around and saw Jack.
"You've been stealing my Thermoses and fudge, you rotten piece of ectoplasm!" Jack shouted.
"I didn't take your fudge, Jack, honest. But you can have your Thermos back," Phantom said, tossing said item at Jack. Jack caught it and watched as the boy flew away.
"Lying ectoplasmic lump, I know you stole my fudge," Jack muttered.

Thinking back to the incident at the Nasty Burger, Jack realized Phantom had probably been with the kids the whole time. How else would he have gotten the Thermos and appeared so soon? He had probably just been invisible! Jack cursed himself for not bringing any ghost-detecting instruments, but he probably would have attributed the readings to the common but unexplainable way they read Danny as a ghost.
"Dad?" Danny asked hesitantly, walking up to where his dad was leaning against the kitchen door.
"I know you've been taking Thermoses from the lab and giving them to Phantom!" Jack said.
Danny opened his mouth, closed it, then opened it again, looking thoughtful. "Dad, I know you don't like me meeting ghosts, but Phantom's different. He—"
"Not you, too!" Jack interrupted. "He has the whole town fooled with his 'hero' guise, even my children, but not me. Oh, no, he can't fool me."
"Dad?" Jazz had walked into the room to see what the commotion was about. "A-Are you okay?"
"Of course I'm okay, Jazzerincess," Jack said. "But Danny here has been smuggling my inventions and my fudge to the evil ghost boy!"
"I never took your fudge!" Danny retorted.
"But you did take my weapons!" Jack yelled triumphantly, though he still didn't believe his fudge was safe.
Danny rubbed the back of his neck with one hand. "Uh, yeah. Sorry, dad, but Phantom needed—"
"What have I told you many times?" Jack interrupted. "Never help ghosts! They might seem nice on the outside, but they're evil, through and through."
"Dad," Jazz said, laying a hand on Jack's arm. "Phantom's different. I think he truly believes he's a good guy."
"Not you, too!" Jack moaned, hugging her tightly. "Next time I see that ghost boy, I'm gonna catch him and tear him apart, molecule by molecule, for what he did to my kids!"
Jack was surprised and confused to hear Danny take a sharp intake of breath.

The next morning, Jack awoke to the sound of something heavy hit the ground. He hurried to the window and saw it was still dark out. He looked down at the street and saw Danny lying in a small crater, clearly in pain. Jack looked up and saw Skulker laughing, floating above the rooftops. It seemed Danny had fought a ghost, in the middle of the night, with little to no weaponry. What was he thinking?!
Jack ran outside with a Thermos, ready to suck Skulker in, but Skulker's words as he taunted Danny made him stop.
"I will have your hide this time, halfa!" Skulker yelled triumphantly. Danny managed a weak "Never..." and Jack uncapped the Thermos. Skulker was sucked inside, spluttering in astonishment. Jack picked Danny up and carried him to his room.
"We'll talk tomorrow," Jack told him.

The next morning, Danny surprised Jack by looking as if he had slept peacefully the whole night instead of being thrown onto the ground for who knew how long.
"Danny, I think we need to have a talk," Jack said. Danny looked so horrified that he started to laugh. "About your ghost hunting."
That caused Maddie to look sharply at Danny. "I didn't know you hunt ghosts."
Danny froze. "Um, sometimes...when I can..."
"Danny," Jack said calmly. "The middle of the night is not a time you can hunt ghosts alone without weapons. There's never a time for that."
"Oh, Danny!" Maddie cried, running to embrace her son. "Are you hurt?"
"Mom, I'm fine," Danny muttered. Jack almost missed the 'help me' look the boy sent Jazz.

After a long talk about waiting for backup, bringing the proper materials, and never forgetting fudge when shopping, Jack let Danny see his friends. While he was out, Jack snuck into his son's room and hid a camera. The next morning, Jack sat down to watch the footage. He saw Danny sleeping, then, at around midnight, Danny sat up and shivered, as if cold. He jumped up and ran out the door. About a half an hour later, Phantom phased through the wall of Danny's room. He looked around, then stared directly at the camera. A small ectoblast formed in his hand, and he fired. The footage turned green, then dissolved into static. (1)

Later that day, as Danny returned home from an afternoon spent on Doomed with Sam and Tucker, Jack confronted him.
"Danny," he said. Danny looked up, worried. "I know you think Phantom's different, but he's not. He's just as evil as the rest if the ghosts. Maybe even more, if he deceives people like this."
"Dad," Danny said calmly. "He's a good guy. You don't know him like I do."
"Do you know that he went into your room last night?"
Danny looked slightly angry. "Dad, did you try to spy on me again?"
"No, Danny-boy. I just wanted to see if you'd go ghost hunting again. But now I know what's going on."
Danny looked worried. "What do you know, dad?"
Jack smiled triumphantly. "I know Phantom stages ghost attacks for you so he can sneak into our house!"
"Dad, you're so far from the truth, it's not even funny," Danny said hesitantly.
"Then enlighten me."
Danny looked at his shoes. "I-I can't."
"Sure you can," Jack said, clapping his son on the shoulder and almost knocking him over.
"Actually, dad, I really, really can't." With that, Danny went to his room and locked the door.

The next day, as Jack was working in the Op. center, Phantom flew by and alighted on the roof. It was very random and foolish, a ghost sitting on the roof of a house of ghost hunters, but he thought nothing of it. Perfect, Jack thought, activating the Fenton Ghost Net. It erupted from the roof and enveloped Phantom. Before he could try and escape, Jack activated the Roof Thermos, and Phantom was sucked in.
The Fenton Ghost Net and Roof Thermos were two of Jack's newest inventions. He hadn't even told his family about them! The Ghost Net was an ultra-strong, phase-proof net that could be remotely activated to wrap around a ghost. The Roof Thermos was just a Fenton Thermos that could be remotely activated. Once the ghost was inside, it could be sent to an another Roof Thermos without actually leaving the first one, giving it no chance of escape. He couldn't make them portable, so he decided that they would work best on a roof. Well, one on a roof, the other in a secure location.
Jack sent Phantom from the Roof Thermos on the roof to the Roof Thermos in the lab, then hurried down himself. He extracted Phantom, still tied up in the net, and deposited him on a sleek, silver table. Phantom looked positively terrified. Only when he was sure Phantom was secured to the table did Jack release the net.
"All right, Phantom, talk." Jack growled.
"About what?" Phantom asked. "The game last night? I'm sure our team would've won if—"
"No," Jack barked. "About Danny. And what you've been doing to him and Jazz."
"Oh, Danny? Your son? Nice guy. And Jazz, too, although she can be a bit annoying—"
Phantom broke off as he was struck by 100 volts of electricity.
"That was for not answering my question. And for calling my daughter annoying."
"All right, all right, sorry. But, you know, you didn't really ask me a question, you kinda just—" Phantom stiffened as Jack's hand neared the button that would shock him again. "Okay! Structure doesn't matter!"
"Now," Jack said, leaning over Phantom. "What have you been doing to my son?"
"Nothing, Jack, I swear!" Phantom gasped.
"We are not on a first name basis, Phantom. You stole my weapons, put false ideas in the heads if my children, and ATE MY FUDGE!"
"Again with the fudge!" Phantom groaned indignantly. "I never touched the stuff!"
"Liar!" Jack spat.
Phantom sighed. "Look, I know you're stuck on the whole 'all ghosts are evil' thing, but we really aren't. Okay, so maybe there are a few evil ghosts out there, but there's evil people too, right?"
"You think you're so human," Jack hissed menacingly. "You say you're not a heartless, evil ghost."
"I'm quite sure I have a heart. And I may not be human, but it's sure better to act like one then your idea of a ghost. I may get a chance to relax rather than being hunted all the time."
"Care to test that theory?" Jack said, thoughtfully examining a sharp-looking knife. "You seem so sure you have a heart..." Jack stood and began to make his way over to Phantom.
"Dad! No!" Phantom shrieked.
Jack's step faltered, a look of bewilderment appearing on his face. "What did you call me?"
Phantom didn't answer, he seemed to be sobbing. Ghosts don't cry, Jack thought, grabbing a vial and catching some of Phantom's tears as the boy glared at him. Maybe he is different.
Jack entered the data into his system and, sure enough, they were real tears. Frowning, he yanked a hair off Phantom's head, ignoring the indignant 'OW!' that came with it.
"Please, Jack! Let me go! I'll buy you more fudge!" Phantom begged.
"To replace what you stole?" Jack growled.
"I NEVER TOOK YOUR FUDGE!" was the indignant reply. Jack simply hit the shock button again, then entered the hair into the computer. To his surprise, not one but two DNA matches showed on the screen. One was, as expected, Danny Phantom. The other was...

Danny Fenton.

His son.

Danny Phantom. Danny Fenton. The names swirled around in his head. He was a fool for not realizing their similarities earlier. He turned to the captive ghost.
"Danny?" he asked hesitantly.
"Dad?" Phantom—no, Danny—whispered.
"The portal. The day of my accident. I guess I got infused with ectoplasm. Or something."
Jack blinked. This went against scientific logic, but all signs pointed to it being the truth. "Show me," he said, unlocking Danny's restraints. Danny sat up rubbing his wrists. Two blue rings appeared around his waist and travelled in opposite directions on his body. When they disappeared, Jack was looking at his son.
"What's a halfa?" Jack said randomly.
"What I am," Danny said. "Half of. Half ghost, half human."
"Are there any more of you?" Jack whispered.
"One that I know of," Danny said hesitantly. Jack got the feeling that wasn't the case, but he wasn't about to press the boy for answers, especially now. "Vlad."
Jack's mouth fell open. "Vladdie? He's a...ghost?"
Danny nodded. "Dad...can I...go now?"
"Of course," Jack replied. As Danny was climbing the stairs, he called out, "I'm sorry."
Danny looked over his shoulder. "I know."

That night, in his bed, Jack couldn't go to sleep. The day's events kept playing in his head. He had shot at, threatened to rip apart molecule by molecule, captured, restrained, electrocuted, and threatened to rip the heart out of his own son! What kind of father was he?! Jack got up, grabbed a piece of fudge, and just stared at it. After a few minutes of contemplation, he brought the fudge to Danny's room on a small plate and knocked on the door. Before the boy could answer it, he left. He didn't know what to say.

The next morning, when Jack came down for breakfast, he stopped in the doorway in shock. Danny, in Phantom form, was eating cereal and chatting to Jazz. Maddie was, thankfully, still in the shower.
"Danny..." Jack said hesitantly. "What's going on?"
"We're going to show mom," Danny said, grinning slightly. "She's going to come down here to see the three of us having a normal conversation. Then I'll change for her, we'll all be happy, and I won't get shot at by you guys any more. Oh, and thanks for the fudge."
Jazz smiled. "Dad, isn't it great we don't have secrets any more?"
Danny just gave her a long look. It was clear that wasn't the case, but it was Danny would decide when to tell them, not Jack.

When Maddie came down and saw the scene at the breakfast table, she pulled out a gun and yelled, "GET OUT OF MY HOUSE, VERMIN!"
Danny calmly turned around, held up a plate of food, and said, "Oh, hi, mom. I made you breakfast."
Maddie spluttered for a second, then regained composure. "Where's Danny? And what are you two doing?! he's right in front of you!"
"I know," Jazz said. Then, turning to Danny, "Time yet?"
Danny glanced at his dad, who shrugged. Danny shrugged too and changed back into his human form. Maddie dropped her gun and fainted.

When she woke up, her family was surrounding her, looking worried.
"I just had the weirdest dream," she murmured.
"That wasn't a dream, mom," Danny said. Maddie frowned.

"Mister, you have lots of explaining to do."

A/N: Mehhh. I hope you like it. It got a little deep there, when Jack find out, but I tired to add a bit of humor, with the fudge...meh. I kinda tried humor at the end, too, but I felt it fell a little flat.
What I'm happy about is the length. Woo-hoo!
I really hope the characters aren't OOC...I tired! If you weren't sure, this was third person POV following Jack. I originally decided to do it following Danny, but then this just...happened. A lot of stuff in this just happened, really :)

1. When Jack filmed Danny's room, the camera sent the footage to the computer. So when Danny destroyed the camera, he didn't destroy the footage, because it was on the computer. Just if anyone was confused :)

Review, pwease! :)