TUESDAY, MAY 12

"90210" � (9:00-10:00 p.m. ET)

"Zero Tolerance" (TV- 14, L) (HDTV)

IT'S PROM NIGHT AT WEST BEVERLY, MUSICAL GROUP THE VERONICAS PERFORM � West Bev's Hollywood-themed prom is full of surprises, but first Harry (Rob Estes) warns his students that any non-school sponsored parties after the prom will be met with serious consequences. Naomi (AnnaLynne McCord) learns that Jen (guest star Sara Foster, "CSI") has maxed out her credit card to furnish their new home, but soon forgets her problems when Liam (Matt Lanter) asks her to the prom. Meanwhile, Liam continues to count down the moments until Annie (Shenae Grimes) shows her true colors, but to prove him wrong, she accepts theater-geek Charlie's (guest star Chuck Carter, "The Big Bang Theory") invitation to the dance. Kelly (Jennie Garth) attempts to warn Ryan (Ryan Eggold) about Jen's devious personality, which he interprets as Kelly's jealousy. Navid (Michael Steger) confronts Ty (guest star Adam Gregory) during a fight about abandoning his soon-to-be child with Adrianna (Jessica Lowndes), but rushes to Adrianna's side when she goes into labor. Dixon (Tristan Wilds) is surprised to learn he's nominated for Prom King, and Silver (Jessica Stroup) is even more surprised when she has the opportunity to speak her mind in front of her peers. Lori Loughlin and Dustin Milligan also star. Nick Marck directed the episode written by Gayle Abrams & Jennie Snyder (#123).