In the first episode of Zetria, the blonde heroine, a Samus look-alike, finds herself in a desperate situation. Her spaceship crashes on an alien planet, and she's infected by a mysterious creature. To heal, she must engage in an otherworldly act. She encounters an alien monster with a colossal cock, and despite her initial hesitation, she mounts it, riding it with reckless abandon. The monster's massive member stretches her tight pussy, filling her with pleasure and alien cum. The game's side-scrolling action pauses as she takes the monster's load, her big tits bouncing with each thrust, her big ass slamming against the monster's body.