LOVE IS POWERFUL ON "THE O.C." THURSDAY, MARCH 31, ON FOX

After Caleb's reveal, Lindsay and Ryan grapple with their relationship: Is Lindsay Ryan's aunt or his girlfriend? Meanwhile, Summer meets Zach's family and it doesn't go so well. In the end it's an anniversary to remember as Sandy Cohen surprises Kirsten with a serenade at the Bait Shop. But Marissa ends up alone as D.J. leaves Newport Beach on "The Power of Love" episode of THE O.C Thursday, March 31 (9:00-10:00 PM ET/PT) on FOX. (OC-208) (TV-PG D, L)

Cast: Peter Gallagher as Sandy Cohen, Benjamin McKenzie as Ryan Atwood, Mischa Barton as Marissa Cooper, Rachel Bilson as Summer, Adam Brody as Seth Cohen, Kelly Rowan as Kirsten Cohen, Tate Donovan as Jimmy Cooper, Melinda Clarke as Julie Cooper, and Alan Dale as Caleb Nichol.

Guest Cast: Michael Cassidy as Zach; Olivia Wilde as Alex; Shannon Lucio as Lindsay; and Nicholas Gonzalez as D.J., Jordan Baker as Elaine; and Devin Sidell as Abigail