Hiroki starts working part-time at a restaurant run by his friend's parents, but while working alongside the mother, Natsuko, he begins to think of her as a member of the opposite sex. Then one night, after work, he misses the last train and ends up staying at Natsuko's house for the night... Unlike at work, she is braless, revealing her voluptuous body, and Hiroki tries desperately to hide his excitement. However, drunk and with her hidden sexual desire exploding, Natsuko can't hold back and leads his hand to her chest...