In the crowded graduation train, two former classmates, Akira and Yui, reunite unexpectedly. Their hidden high school affection ignites in the confined space, leading to yearning kisses and desperate groping. Amidst the jostling passengers, they surrender to intense passion, their moans muffled by the rhythmic train sounds, exploring each other with a mixture of nostalgia and raw, unleashed desire in this forbidden, public encounter.