Codenamed "Apex," legendary marksman Kim and the Kaiju Caesar fought side by side, becoming heroes who protected humanity's cities from the devastation of mutant creatures. But after his wife was killed by one of the Kaiju, Kim swore never to pick up a gun or be drawn into another war. Hiding his true identity, he lives as a humble janitor, devoted only to protecting his daughter. When mutant creatures suddenly attack her school, disaster strikes. With humanity on the brink once again, the legendary marksman is about to return!