CASTLE Season 5 Episode 24 Watershed Promo : CASTLE – “Watershed” – 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, on “Castle,” MONDAY, MAY 13 (10:01-11:00 p.m., ET) on the ABC Television Network