Disclaimer: It all belongs to the almighty Joss.
AN: This AU is assuming that Billy and Penny started going out a few weeks before Act I.
"Billy, what is this?"
Absently adjusting his goggles so that they stopped slipping over his eyes, Billy peered intently at the bag that was now hovering in front of his face. He became distinctly aware of a blush burning up his cheeks and mumbled half-heartedly, "It's cumin."
Penny stabbed at the bag with her fingers until the substance inside wobbled and sloshed in a highly disturbing manner. Her eyebrows did that truly remarkable dance that she had perfected over the few weeks that they had been going out. Usually the dance made an appearance when she'd figured out what sort of scheme he was up to. Billy tried to swallow, but found his throat dry.
"Cumin," repeated Penny calmly, "Since when do you cook?"
"Well, since today obviously. But as you can probably tell, I may have slightly overdone the cumin."
Penny sniffed at the side of the bag, though she didn't look entirely convinced. "You don't cook cumin by itself. It's an additive."
"I realise this now," Billy countered as firmly as he dared.
Inwardly, he was feeling pretty smug right about now. Enough that the traitorous blush working its way to the back of his neck felt like it was cooling down a bit. Penny opened the bag and pressed her nose close to the opening, frowning again. She dipped one finger into the liquid momentarily before gagging. "Eugh. This feels like snot."
"Heh, tell your friends, dinner with Dr Horrible – a truly fine culinary experience."
"Except I know you, Billy," Penny said firmly, closing the bag, "And I know if I didn't make you dinner, you'd end up living off frozen yoghurt."
Uh oh. Billy didn't like where this was headed. He reached feebly for the bag but she took a few steps away from him. His hand aborted the attempt and instead settled on his goggles, fiddling nervously. He said weakly, "If it looks like a duck and quacks like a duck…"
"Cumin doesn't quack."
"If it smells like cumin and looks like cumin…"
"Except that it doesn't look like cumin," Penny finished, setting aside the bag and crossing her arms. "If I loaded up your blog, I wouldn't happen to discover exactly where this came from, would I?"
Slumping his shoulders, Billy studied the floor intently before raising his most appeasing lost smile up at her. It wasn't too long before the story came rushing out – interspersed with triumphant giggles and grovelling – and as expected, she didn't look terribly pleased. Penny sighed and eyed the bag a little apprehensively.
"I would have thought gold might be more useful in bar form," she said after a while.
Here, Billy felt he could defend himself. "It's not about using it, it's about taking it! What were they going to do with those anyway? At least this way I can try out my experiments and the gold gets to go towards something useful."
Penny dropped into a nearby chair and wheeled it over to sit in front of him. Taking his hands in hers, she gave him an even stare until he reluctantly stopped darting his eyes around for the nearest exit.
"I worry about you, Billy," she said softly, "You might try keeping your plans out of your blog. What if the police saw a record of your activities? And I know you don't mean much harm by what you're doing, but I believe you can use your gifts for better and greater things."
"You're right. I should upgrade to that Wonderflonium heist."
He probably deserved the exasperated look she gave him. Squeezing her hands in response, Billy promised, "I'll try to keep the important schemes to myself, but you know I have to give my loyal viewers something. They expect tales of woe and mad genius…are you mad at me still? Please don't be mad. I'd put it back if I could but I don't think bags of cumin-smelling gold-goo will be too popular…"
"I'm not mad," Penny interrupted, "But I'm sure you can find a way to transport them back properly."
"Or I could turn the goo into bars for the homeless shelter!" Billy rejoined brightly.
"I wouldn't accept that money. It wouldn't be right."
He coughed and nodded. "Or I could just find a way to return it, an excellent point."
"I'm glad to hear that." Penny gave him her best smile. "I wouldn't want to have to start calling you Robin Horrible, because I don't think that name would suit you at all."
"You know…like Robin Hood."
Her laugh made very pleasant warm tingles flutter around his stomach. Billy decided he liked this and shyly shifted his goggles, gazing at her hopefully. He knew he could get away with a lot of things just by flashing his eyes at her. He knew she liked blue eyes. Penny laughed again, his intestines performed a happy jig and then she kissed him, right on cue.
Billy thought it might not be a good idea to tell her about the application he'd sent in to the Evil League of Evil. Especially not when he was so enjoyably occupied.