Susan Sullivan, Nathan Fillion Photo

From: Photo Flash: First Look at CASTLE's 100th Episode, Airing 4/1

On CASTLE's upcoming episode, titled 'The Lives of Others,' in the show's 100th episode, Castle finds himself in the unfortunate position of NOT being able to work a case. While he's holed up in the loft with a broken leg, Beckett goes off to investigate the death of an IRS agent without him, leaving Castle miserable and bored. But when he thinks he witnesses the murder of a young woman in the apartment across the street, he is thrown into a 'Rear Window'-esque murder mystery that hits much too close to home, on MONDAY, APRIL 1 (10:01-11:00 p.m., ET), on ABC.