Patricia Arquette, Medium

Monday night's Medium will be a family affair for star Patricia Arquette.

Not only does the episode, titled "A Person of Interest," mark Arquette's directorial debut, but it also guest-stars her son, Enzo Rossi. "He plays a boy who's an egg-headed, scientific kid, and his dad is like a real weirdo," Arquette told TVGuide.com on the red carpet for The Heart Truth's Red Dress Collection 2009 fashion show.

In the episode, a crime scene leaves a strange impact on Allison, whose odd behavior plays a key role in unlocking a 17-year-old crime.

"We also have Anjelica Huston's coming back, Blythe Danner, David Morse and Tracy Pollan, so we have a lot of great guest stars," she said.