Synopsis by Tracie Cooper
The group's suspicions about Tess (Emilie de Ravin) are further heightened when she kisses Max (Jason Behr) in full view of Liz (Shiri Appleby), who begrudgingly accepts Max's explanation that he had no control over his actions. Despite Isabel (Katherine Heigl) and Michael's (Brendan Fehr) search for Tess' true identity, neither can find information suggesting that she is anything other than a normal high-school student. When Liz gets herself in trouble at Tess' house, the kids come to rescue her, and make a startling discovery in the process: it looks as if Tess is none other than the fourth alien. Meanwhile, Agent Topolski (Julie Benz) is killed, and Sheriff Valenti (William Sadler) tries to gain Max's trust.
alien [not human], double-agent, high-school, kiss, secret-identity, sheriff, teenagers