Keikenzumi na Kimi to, Keiken Zero na Ore ga, Otsukiai suru Hanashi. EP6 - Our Cheating Story: The Experienced You Cheats with an Experienced Someone Else?

The person who called Ryuto to the gym at night was actually Maria. She confesses her desperation to become Ryuto's first, even if that means dressing and acting like Runa. Ryuto is shocked. As the two talk it out, someone else watches from the shadows.