Nathan Fillion will be reunited with his Firefly co-star Adam Baldwin (formerly the man they call Jayne) on Castle this Monday. Baldwin is set to guest star as tough guy Ethan Slaughter, a detective from the NYPD gang unit, opposite Fillion’s Rick Castle. Read on for three sneak peeks and the episode description for “Headhunters” … Continue reading Nathan Fillion & Adam Baldwin together again on Castle [Sneak Peek]