Nick (David Giuntoli) and Hank (Russell Hornsby) are on the case after a mysterious creature devours a man who went fishing on Diamond Lake. The pair interviews the brothers who run the boat rental place, Oliver and Wayne, and Nick catches one of them Woge, but not into anything that resembles the Diamond Lake Monster of yore. In fact, the brothers have hired Logan, a Wasser Zahne, to pose as the monster to drum up business. Though Logan wasn't supposed to kill anyone, the money convinces Wayne to contract Logan again, which leads to another death and even more revenue. But when Logan sees how much money the brothers are making, he wants in or he'll kill them, too.
Wayne decides he and Oliver need to kill Logan, but his plan is interrupted by Trubel's (Jacqueline Toboni) arrival. She reveals she's a Grimm and looking to collect the bounty placed on the monster. Sensing an opportunity, Wayne convinces Trubel to come back later that night and dispatch Logan for half of the profits. Trubel agrees, then returns to Nick and Hank and tells them everything. At the same time, Wayne goes to Logan and asks him to kill Oliver, as well as tips him off about Trubel. Believing Oliver set him up, Logan arrives ready to kill him, but Trubel soon takes him out. Nick and Hank then run in and corner Wayne. He Woges and jumps into the lake, causing the gathered monster hunters to mistake him for their prized beast. Wayne is killed, along with the myth of the Diamond Lake Monster.
