A man finds mutilated cows in a field and is confronted by a glowing blue skinned Wesen, who inadvertently kills him by pushing him into a fence post.
The Wesen is a Glühenvolk named Vincent (Eric Tiede), who has been mutilating cows to feed their ovaries to his pregnant wife, Jocelyn (Erin Way).
Nick and Wu (Reggie Lee) investigate the killing, with Hadley stating the Wesen was an alien.
While Nick and Wu find a piece of the skin of the Wesen, Lazure seems to know about the incident and manages to identify the "alien" from a witness.
Club's Kevin McFarland gave the episode a "B−" grade and wrote, "'Endangered' doesn’t go for the alien abduction or invasion story.
It's a familiar arc, but Bree Turner and Silas Weir Mitchell's performances, amazed and curious with ever-improving chemistry, sell it well.
The creatures, who turn glowing blue when agitated thanks to a hormone for bioluminescence (I haven't seen Avatar in a long time, so my below-rudimentary knowledge of this part of biochemistry is practically nonexistent), are on the run from Nebraska, aiming to get to Alaska to meet up with more of their kind.
"[4] Nick McHatton from TV Fanatic, gave a 4.0 star rating out of 5, stating: "'Endangered' was one of the better installments to introduce new viewers this far into the season, thanks a mostly predominant procedural case and light, easy to follow serial elements.
Plus, I appreciated the recap of the whole key business, Juliette finally coming around, and Renard continuing to be a pretty good ally for Nick.