Cathrine Grace

Preston and Porter move out; Gaby and Carlos visit her hometown; Keith asks Bree to move with him to Florida; Susan uses her ailment to get special treatment; Paul makes a decision about Beth.

Meredith and Lexie's father returns to Seattle Grace with stomach pains and a new girlfriend; Alex butts heads with the new OB; Mark bribes Jackson for information on Lexie.

Reese inadvertently perfects Malcolm and Stevie's science experiment, but can't remember how he did it; Dewey dreams up reasons for people to buy the candy he's selling door-to-door; and Francis aids a piglet.

Grissom, Warrick, and Sara investigate when a woman vanishes while taking part in a magician's act. (TV-PG)

An unreliable witness and an overzealous detective hinder a murder investigation; a con artist scam leads the squad to a sex-slavery operation; McDowell agrees to join Sipowicz and Theo at a theme park.

After the suspicious death of her mentor, Dr. Ann Coulter, bio-anthropologist Dr. Sloan Parker continues their study of a serial killer's DNA and, together with Dr. Ed Tate, discovers a new humanoid species that could replace humans.