Doug Ballard

Leo fears the worst when he testifies in the congressional investigation into Bartlet's lack of public disclosure about his illness.

The Cohen family prepares for a visit from Sandy's mother, Sophie (Linda Lavin - "Alice"), for Passover dinner. Fearing that his grandmother will not approve of Summer, Seth tries to keep the two from encountering each other--but Summer sets out to prove him wrong. Meanwhile, Ryan desperately searches for Marissa, who disappeared when she found out about Luke and Julie's affair.

After Luke gets into a near-fatal accident, Marissa and Ryan decide it is time to hear what he has to say; just prior to the Lighthouse's opening, Jimmy and Sandy find out their liquor license has been denied; Caleb proposes to Julie.

The full moon and festivities prompt strange happenings including Blanche's jewelry being swiped, Sophia trying to break a curse and Dorothy and Miles sharing a passionate kiss.

Grace (Debra Messing) discovers that one of Karen's (Megan Mullally) friends is the notorious Helena Barnes (guest star Joan Collins, "Dynasty"), one of New York's most-celebrated interior designers, and her primary competition for a lucrative design job. Meanwhile, Jack (Sean Hayes) might regret it when he convinces Will (Eric McCormack) to help him try to obtain financing for his latest venture, The Subway Tush - a portable seat to make subway rides comfy.