You can watch Season 3, Episode 7, titled " Cold Blooded ," through various official streaming and purchase platforms. Originally aired on December 13, 2013, the episode follows Nick as he investigates a deadly crime spree involving an urban legend in the sewers. Where to Watch Watch Grimm Season 3 | Prime Video - Amazon.com Watch Grimm Season 3 | Prime Video. Menu. Browse. Amazon.com Cold Blooded - Grimm (Season 3, Episode 7) - Apple TV