The one where: Veronica finally solves her date rape.
Eclipsed by: "Leave it to Beaver" (season 1 finale)
"Who killed Lilly Kane?" is basically the first season's tagline, but the pilot presents another mystery too: Who date raped Veronica? In the first episode, it's presented as more of a character development, one that informs Veronica's social standing and the shitty moral compass of her classmates (and the sheriff), than an actual mystery to be solved, thus explaining why it doesn't come up again until our heroine gets an unexpected lead at the end of the season. It all comes to a head in the penultimate episode, which puts Veronica on the emotional rollercoaster until she gets to the uncomfortable truth.
But what really makes the episode special is the way it trots out every supporting player and case-of-the-week guest star, both for an encore before the season gets back to Lilly Kane business and because Veronica's attack happened at the "biggest party of the year." By including every character of note, Neptune, high school and town, and by extension the Veronica Mars universe on the whole, feels lived-in and real. This is the episode that truly made Neptune High one of the most memorable schools in any teen show, ever. —Frazier Tharpe