When does Grimm return?

The series aired from October 28, 2011, to March 31, 2017, for 123 episodes, over six seasons. The narrative follows Portland homicide detective Nicholas Burkhardt (played by David Giuntoli) who discovers he is a Grimm, the latest in a line of guardians who is sworn to keep the balance between humanity and mythological creatures, known as Wesen. The series initially garnered mixed reviews from critics, though reception grew more favorable throughout series' run.