FBI agent Topolsky returns to warn Liz that a covert alien hunter inside the Bureau is pursuing Max and his friends -- and that he will stop at nothing to get what he wants. Meanwhile, Isabel befriends Tess, a new female student who immediately arouses Max and Michael's suspicions.
Elenco: Jason Behr , Katherine Heigl , Brendan Fehr , Shiri Appleby , Majandra Delfino , William Sadler , Nick Wechsler , Adam Rodríguez .