Career woman Sayaka works for a large company, and she is well-liked by her colleagues because she always smiles and is thought to be a gentle person. However, she actually has a tremendous sexual desire that cannot be maintained unless she masturbates. One day, a junior colleague named Himari suddenly shows up after missing the last train, and she is forced to stay over... Sayaka, who was forced to have an impromptu no-appointment sharing room banishment, eventually loses her reason and starts masturbating with the junior colleague's belongings...