Kore mo Rippa na Undou desu!

A young man named Kaito finds himself in an awkward situation when his childhood friend, Yui, accidentally walks in on him while he is changing. To make matters worse, Yui is a fitness enthusiast who believes that physical activity is the solution to all of life's problems. She decides to help Kaito get in shape by incorporating him into her daily exercise routine, but her methods are unconventional and increasingly intimate. As they work out together, their friendship begins to blur into something more, leading to a series of steamy encounters that challenge their boundaries.