Sela. Robyn Hood. Red Riding Hood. Captain Hook. Neptune, God of the Sea. Van Helsing. On their own, they are some of the most powerful beings in the Grimm Universe... but together, they are the Realm Knights!

When Cronus, the Titan that fathered Zeus, wages war on Earth, it falls to the government's newly formed Realm Knights to save the world. But can these heroes who are each used to working alone hash out their differences in time to come together and stop an ancient threat?