Grimm is back on Friday with an all new episode, 4×13 ‘Trial by Fire’, watch the trailer above and read the synopsis below!

Plot summary – When an arson case looks to have Wesen origins, Nick (David Giuntoli) find himself reluctantly having to ask an old foe for help. Elsewhere, Viktor (guest star Alexis Denisof) teaches Adalind (Claire Coffee) the effectiveness of well-played diplomacy. Meanwhile, Juliette (Bitsie Tulloch) finds herself in a confrontation sooner than expected. Russell Hornsby, Silas Weir Mitchell, Sasha Roiz, Reggie Lee and Bree Turner also star