Todo Sojuro, a mercenary instructor, and his student Sylpha survive the war together. Upon returning to Japan, Sojuro finds himself developing feelings for Sylpha, the orphan he brought home. Wanting her to experience a normal life, he chooses to step back. Unexpectedly, Sylpha reveals her love for Sojuro as well, setting the stage for a comedic tale of love between the former mentor and student cohabiting under one roof.