The war begins in this Friday's Grimm finale "Cry Havoc"

This Friday the war between the Royals and team Grimm begins! After Nick discovered the shocking death of his mother - where his ex-girlfriend had a hand on it - he is hell bent and is ready to fight. Now with Trubel back in Portland, they are well prepared for it.

According to Bree Turner, it will be the "finale of all finales". So we have to expect something big! Here's what you have to know for the finale of Grimm Season 4:

A HORRIFYING DISCOVERY SETS NICK ON A WAR PATH - JACQUELINE TOBONI AND NICO EVERS-SWINDELL GUEST STAR

On the heels of a shocking discovery, Nick (David Giuntoli) is hell bent on getting revenge and taking the fight to the Royals with help from Trubel (guest star Jacqueline Toboni). Meanwhile, Juliette's (Bitsie Tulloch) alliance continues to lead her down a dark path. Russell Hornsby, Silas Weir Mitchell, Sasha Roiz, Reggie Lee, Bree Turner and Claire Coffee also star.