In the season finale, an interview with a high-profile federal law enforcement agency forces Beckett to reconsider what she wants out of her job and out of her relationship with Castle. Meanwhile, the body of a young woman is found floating inside the water tank of a skid row flop house, but as the team investigate, they discover that her final resting place is just one of many strange things about her death

Castle - Episode 5.24 - Watershed (Season Finale) - Synopsis | Spoilers