My anticipation for season two of the high school shamus series Veronica Mars was almost mirthful, an emotion admittedly paradoxical to the reality of teenagers having to face another school year of homework, peer ostracization and crazy authority figures. But I was wary in one regard: Would UPN take obvious and quality-degrading measures to turn a ratings-deficient but cult-popular show into a breakout hit? Like the show’s clue-hunting title character, I was on the case as I watched the first two episodes. So far, so good, although I detect a few network fingerprints. For one thing, sex is in the air. Everyone’s hooked up now: Veronica’s meeting back-in-the-picture beau Duncan in hotel rooms; PI daddy Mars is seeing Wallace’s mom; Wallace is macking on the new rich girl (Tessa Thompson), even solving his own cases; and Logan’s trysting with his friend’s stepmom, played with Maxim-ized brio by curvy-yet-caustic Buffy/Angel alum Charisma Carpenter. Last season, sex was a carefully broached, dark-cloud topic — especially considering the central mystery of who raped Veronica — but this year, UPN is clearly hoping a preponderance of hooking up will hook in viewers. It’s hardly a quibble, though. Leave it to the writers to emotionally upstage the skin quotient with a horrific, sinister, student-killing bus crash that has thrown the fictitious Neptune High into a den of guilt, anger, suspicion and media exploitation. They won’t let us forget — no matter how big a metaphor it takes — that high school to high schoolers can often feel like the end of the world.