TUESDAY, OCTOBER 20

"90210" � (8:00-9:00 p.m. ET)

"Unmasked" (TV-PG) (HDTV)

JENNIE GARTH AND ANN GILLESPIE GUEST STAR IN THE HALLOWEEN- THEMED EPISODE � It's Halloween at the Beverly Hills Beach Club and Adrianna (Jessica Lowndes) channels Marilyn Monroe to help her deal with the end of her relationship with Navid (Michael Steger). Silver (Jessica Stroup) and Kelly (Jennie Garth) continue to have differing opinions about caring for Jackie (Ann Gillespie). Silver is overloaded with school work and caring for her mom, but soon learns that she and Teddy (Teddy Donovan) have more in common than a class project. Naomi (AnnaLynne McCord) continues her relationship with Richard (guest star Jonathon Trent, "CSI: NY"), but when she and Jamie (guest star Travis Van Winkle, "Meet the Spartans") share an intimate conversation, her plans to schmooze with the dean of CU come to a screeching halt. Dixon (Tristan Wilds) realizes he and Sasha (guest star Mekia Cox, "Bones") are in two different places in their life and decides to end their relationship, but she ends up delivering life-changing news. Tensions rise between Debbie (Lori Loughlin) and Harry (Rob Estes) when she walks in on Harry and Kelly in his office. Annie (Shenae Grimes) and Jasper's (guest star Zach Sherman) relationship is put to the test when he attempts to convince her to steal a car while shooting a scene for his student film. Liam (Matt Lanter) butts heads with the newest member of the surf team, Ivy (guest star Gillian Zinser). Ryan Eggold also stars. Miller Tobin directed the episode written by Jennie Snyder Urman (#207).