Arthur Lane, a graduating senior with no sign of awakening his Beast Soul, faces his last chance at a make-up test that will determine if he graduates. Despite being an F-ranked Beast Soul, far weaker than his sister Jessica and other students like the S-ranked Nancy Cole, Arthur resists pressure to prove himself. During the test, Arthur unexpectedly triggers a powerful energy surge, hinting at awakening an SSS-ranked Beast Soul. This shocking development leaves everyone stunned and raises urgent questions about Arthur's true potential and future.