Bullied and desperate to become stronger, Emi decides to join the judo club. The club is run by Mia, a perverted lesbian woman. As part of the initiation test, Emi must endure a choking technique demonstration, which she barely survives to pass. Mia chokes her until she loses consciousness, then proceeds to molest her while she's out. When Emi regains consciousness, she feels confused but gradually gets drawn into Mia's rhythm. Soon, Mia tempts Emi to choke her back, leading to an increasingly intense lesbian relationship. A strange lesbian world slowly unfolds before them.