Miku, introduced by a coworker, comes to give a massage to relieve muscle tension. Although her reputation is good, her technique feels a bit unusual. The office lady feels confused at first, but before she realizes it, her legs are spread open. As Miku's hands move, her vagina is stimulated, and eventually she reaches orgasm in the cowgirl position. Surprised by the sudden pleasure, she can no longer suppress her arousal.