Returning Drama, 10-11 PM, ABC

By EW Staff
Updated September 10, 2010 at 12:00 PM EDT

Unrequited partners in crime Castle (Nathan Fillion) and Beckett (Stana Katic) will spend much of season 3 ”in relationships with the wrong people,” explains exec producer Andrew Marlowe, referring to the former’s rekindled romance with his ex Gina (Monet Mazur) and the latter’s new entanglement with a hot biker dude (Melrose Place‘s Victor Webster). The tension will also be amped up with the arrival of a serial killer known as the Triple Killer (he kills in threes), who will menace Castle and Beckett on and off all season. ”We wanted to introduce someone who was more of a worthy opponent,” notes Marlowe. Castle may find his biggest foe is closer to home when daughter Alexis (Molly C. Quinn) gets her first serious boyfriend (The Secret Life of the American Teenager‘s Ken Baumann). Says Marlowe: ”This is the first time Castle has to deal with her being in a relationship.” SEPT. 20