This story is in-canon for Season 7, sometime between "First Date" and "Lies My Parents Told Me", with appropriate SPOILER ALERTS.
Well, apparently people have been suggesting some kind of BtVS/Kolchak: The Night Stalker crossover for years, as I myself have since becoming a Buffy fan during Season 6. But so far, I've found only one such effort on the web, so here's my own stab at it. For those interested who haven't already seen them, I also have other spec scripts for what is essentially a crossover of The Wonder Years and Tour of Duty.
Since BtVS has already wrapped as of this posting, and the great Darren McGavin has reportedly retired from acting due to health reasons (and is also mourning the recent passing of his wife of 33 years), it's obviously never going to actually happen. But this is my salute to a great actor and to two great TV series.
Of course, health and retirement issues notwithstanding, this script is written with Mr. McGavin in mind. Other actors I have in mind for other guest roles are noted as the characters make their appearance.
Any allusions within this story to Mark Twain's Adventures of Tom Sawyer are the result of a happy accident rather than deliberate design. When you have two sisters, one of whose given name is Buffy and the other who is called Dawnie more often than not, it just seems more natural that an aunt named Pauline (whose existence had been established back in Season 4) would be called "Aunt Polly" rather than "Aunt Pauline". As for chases and knife fights in a labyrinth of underground caverns, those are at least as much a part of the Buffyverse as they are of the Sawyerverse!
NOTE: Since originally writing this script, I've learned that there is argument over the actual name of Buffy's aunt; I had originally read a copy of the shooting script for the Season 4 episode "Pangs" where Buffy refers to her "Aunt Pauline"; but have since reviewed a tape of the episode where it comes out sounding more like "Aunt Darlene" or "Aunt Arlene" and the closed captioning actually reads "Darlene". With the conflict and ambiguity, however, I've decided to stick with "Pauline/Polly" specifically because of the allusion to Tom Sawyer. Canonical purists are welcome to save this screenplay to a word processing application and use the Find/Replace function to substitute "Darlene" (or "Arlene") for Pauline/Polly, but it's my script and I'm sticking to it!
As I said, this is in-canon, at least as I understand the term. Some may quibble about the revelation that Carl has for Dawn, but I do not believe that it would impact on the rest of the series that significantly.
Feedback is invited.
EXT THE SUMMERS HOME BACKYARD-- MORNING. Buffy stands supervising along the sidelines while Kennedy leads the other Potentials in calisthenics and martial arts exercises.
INT THE DINING ROOM. Dawn, Willow and Xander finish eating breakfast together, with Willow simultaneously surfing the web on her iBook. They converse ad lib as the DOORBELL RINGS.
I'll get it.
INT THE FOYER/LIVING ROOM as Dawn opens the door, and we see CARL standing outside. He is a medium-tall man in his seventies, wearing a rumpled off-white seersucker suit and a straw homburg. As he removes the hat, we see thinning and graying red hair. He smiles.
Yes, can I help you?
Good morning. Is this the home of Mrs. Joyce Summers?
I'm sorry. She... she passed away two years ago.
Carl's face falls. He blinks.
Oh. I'm so sorry to hear that.
I'm her daughter Dawn. My sister Buffy's outside in back....
Carl smiles at her, his eyes getting a little misty.
Maybe one of us can help you, Mr....
Kohl. Carl Kohl. I'm a friend of your mom's family. Actually an old, old friend of your grandmother's. I'm going to be here in Sunnydale for a few weeks and thought I'd look up your mother. So you're Dawn!
Pleased to meet you, Mr. Kohl.
She extends her hand (actually checking to make sure he's corporeal and warm-blooded). He takes her hand in both of his.
Call me Carl. And I'm pleased to meet you, Dawn.
Won't you please come in and have a seat. Buffy should be back inside in a few minutes.
Carl steps inside as Dawn gestures toward the dining room where Willow and Xander turn toward them.
These are our friends, Willow and Xander. This is Carl. He says he's an old friend of my mom and grandma.
Carl, Willow and Xander exchange "Hi!"s, each with a bit of curiosity and suspicion. Carl follows Dawn into the living room, then pauses to look at the pictures on the ledge on the stairwell wall.
INSERT CARL'S POV panning across the ledge. We see a studio family portrait of Joyce, Buffy and Dawn; a solo portrait of Joyce; and an old snapshot of a young blonde woman with two blonde haired little girls; their clothing dates the snapshot as from the early 1960s.
Carl stares at the photos in deep thought as Dawn looks at him.
Dawn, if you don't mind my asking, how did your mom die?
She... she had a brain aneurysm.
And how's your grandmother?
Grandma's fine. She has a nice condo in a retirement community, all the way down in La Jolla, so we don't get to see much of her. She doesn't call that often, either.
And your Aunt Pau....
The last of his words are drowned out as we hear the RACKET of the Potentials coming in the back door and crowding into the kitchen and dining room and starting their breakfast. After a few seconds, Buffy enters from the dining room.
Dawnie, Willow says we have a visitor?
Carl smiles at her with the same misty eyes he had for Dawn earlier.
Buffy, this is Mr. Carl Kohl. Carl, this is my sister Buffy. Carl says he's an old friend of Grandma's.
Buffy extends her hand, and Carl, as with Dawn's earlier, takes it in both of his.
Please excuse the noise. I kind of run a self-defense class for teenage girls as a sideline. We're taking a break.
He came here looking for Mom. He didn't know.
I just moved here to Sunnydale. Temporarily.
And how do you know our grandmom?
I actually worked closely with your grandfather for years. We were investigative reporters together back in Las Vegas in the Fifties and Sixties.
Please have a seat, Mr. Kohl.
Carl seats himself, as Buffy and Dawn sit on the couch facing him.
Please. Call me Carl.
So what was our grandfather like? Mom barely remembered him, and Grandma never talks much about him.
Kirk Wilson... Kirk was a crazy, impetuous sonofab... sonofagun. Once he was onto a story, he'd sink his teeth into it like a pit bull. Wouldn't let his superiors or anyone else make him back off or throw him off the scent, if he knew he was right.
Too hardheaded for his own good at times.
Sounds like something we both inherited!
Is that why he died so young? Grandma never even told us what he died of.
It did contribute to his demise.
Spike enters from the back of the room at the basement steps.
Good morning, Luv! Good morning, Niblet! And who have we got...
Carl turns toward him. They look at each other with vague recognition.
Spike, this is Carl. Carl, this is Spike. Spike's one of my... martial arts trainers.
Good to meet you, Mate!
Carl's a friend of our mom's family. He knew our grandparents.
Carl and Spike continue looking at each other. Carl has a sense of curiosity and wonder beyond the mutual vague recognition.
So, Spike. Where are you from? You look familiar.
I was just thinking the same thing. London, originally, but been kind of all over. How about you?
New York, originally, then Vegas, then Chicago. But kind of all over too.
We'll figure it out eventually.
So, Carl. What brings you to Sunnydale? It's not exactly the retirement capital of the world!
The fact that it's not the retirement capital of the world, when it should be. I still investigate and report freelance on occasion. I'm on a long-term assignment on why the property values here have declined so much, and the municipal government's plans for reviving the economy....
We hear the RACKET in the kitchen and dining room escalate into an argument among several of the Potentials. Buffy turns toward the noise in alarm.
It looks like I caught you at a bad time.
As a matter of fact... but please come again, Carl. I want to learn more about my grandfather!
I'll be sure and do that, Buffy. And I'm staying at the Hancock Inn, room 201. My last name is spelled K-O-H-L.
She rushes back to the dining room.
I'll see you to the door.
Looking forward to seeing you again, Carl. We've got to figure out where we know each other from.
Well, I'm sure we will, sooner or later.
EXT THE SUMMERS HOME. As Dawn smiles and closes the door behind him, Carl walks to the curb where his car, a new silver Mercedes coupe, is parked. His weathered face reflects a myriad of emotions; grief, joy, apprehension are the most predominant. As he gets in the car, he pulls back his jacket and we see, in an elaborate shoulder holster rig, an ornately carved and polished wooden stake.
END TEASER. INSERT OPENING CREDITS