SPOILERS!!!
Scarecrow boy opens up the control panel for the fire sprinklers. His plan, apparently, was to trigger the sprinklers then electrocute everyone (“The sprinklers get them wet, I take care of the rest.”), but Clark interferes, saying things along the lines of “You’re not going to hurt my friends…these people didn’t do anything to you.”
Sparky jump starts a pickup truck and rams Clark. Clark hangs on to the hood, and eventually sparky rams the truck, and Clark, into a wall and a water main. Water floods into the cab, and Sparky sparks up in a very pretty light show, and passes out.
Afterwards, he has amnesia. Which is no surprise, since everybody who knows a superhero’s secret invariably gets amnesia. Or dies.
Clark goes into the gym to see Lana dancing with jock. The two of them are homecoming queen and king, respectively. They share a tender kiss on the middle of the dance floor. Clark, understandably upset (in a somber kind of way), leaves. As he passes the parking lot, he sees three shiny pickups (lot of those in Smallville, apparently), that belong, we understand, to the jocks.
Clark smiles.
<commercial, IIRC>
We see people exiting the gym. They’re pointing in the general direction of the parking lot and laughing. LL and her jock leave. Camera pans over to the three pickups stacked up on each other. Lana looks over towards where Clark exited, though it’s uncertain whether or not she saw him.
Cut to Clark in the loft of the barn, staring at the stars through his telescope. (Aside: Why’s he need a telescope to play peeping tom?) His dad comes up, gives some history of the telescope (“Your grandfather gave that to me when I was your age…”) then leaves.
Clark turns on the radio, typical WB music plays. Lana appears, telling Clark that she didn’t see him at the dance. “What are you doing here,” he asks.
“I saved you that dance,” she says. They dance.
Horns sound outside. Lana disappears, as she was never really there.
Clark looks out the window to see Lana walking into her house. He thanks her for the dance, and she looks around, almost as if she heard him.
The camera pans up to the sky, and we fade to black.