Plumed Serpent (Grimm)

Opening quote: "Said the dragon, 'Many knights have left their lives here, I shall soon have an end for you, too,' and he breathed fire out of seven jaws."

Two robbers break into a warehouse to steal copper wire and are killed by a dragonlike creature, a Dämonfeuer. Nick (David Giuntoli) and Hank (Russell Hornsby) investigate. They go back after the warehouse's owner is attacked. As they corner their suspect, Wu (Reggie Lee) is sprayed with oil and has to retreat. Nick ducks away as the man breathes out fire.

The suspect is identified as Fred Eberhart (Don Alder), an unemployed welder with no known address and a scarred face. His daughter, Ariel (Danielle Panabaker), works in a nightclub as a fire eater. Nick goes there. Monroe (Silas Weir Mitchell) is in the audience; he tells Nick that Ariel is a Dämonfeuer. He also tells him a Grimm was recently beheaded in Europe, possibly by Reapers, and advises him to watch his back.

Nick questions Ariel, then tails her to her home. She attacks him and pins him to the ground – and kisses him. When Juliette (Bitsie Tulloch) calls, Ariel answers Nick's phone and pretends that she and Nick are fooling around. Nick grabs the phone back, but Juliette has already hung up, and he leaves abruptly. At home, Juliette grills him about why he was there without his partner, Hank.

Ariel calls Nick and promises to tell him everything she knows. He phones Juliette to say that he and Hank are going to see Ariel, together. Satisfied, Juliette laughingly promises a fire dance of their own when he comes home. Nick and Hank find Ariel's house is adorned throughout in copper wire. They leave hastily as a lightning storm approaches. Nick arrives home to discover Ariel in their bed. He demands to know where Juliette is. Ariel breathes out fumes and escapes, but then calls back on Juliette's phone, telling him to meet her – but with "no cops".

Nick drives while he and Monroe figure out what to do. Monroe realizes that Ariel has created a "classic quest scenario" and identifies an old train tunnel that must be Fred Eberhart's lair. They arrive and spot Juliette's car. Nick plans to keep Fred fighting while Monroe frees Juliette and takes her outside. Fred proves too strong, however, and Nick is forced to kill him, inadvertently giving him the dignified death Ariel had planned. Now, she says, it is her turn. Nick races out as Ariel chants a poem and ignites a plume of fire. Nick, Juliette and Monroe relax, assuming Ariel is dead.

Driving home, Nick apologizes but tells Juliette he cannot promise that things will get any better. In turn, Juliette cannot promise she can keep 'doing this', but in any case is too tired to talk about it now. Nick remembers his aunt's injunction that he leave Juliette, for her own good.

Meanwhile, Ariel walks out of the tunnel, unscathed.

• "Plumed Serpent" at IMDb