Ken Usato is an ordinary high school student caught in a summoning meant for his two student council classmates, Suzune Inukami and Kazuki Ryusen, who are declared heroes of the Llinger Kingdom. Usato's only ability is healing magic, ranked support tier with no combat application, until Rose, the captain of the Rescue Squad, recognizes that healing applied to the caster's own body can push physical limits far past normal human thresholds. She conscripts Usato into a training regime built to weaponize recovery.