I want to eat a sisters combo! While having sex with his wife, Chang-seok accidentally sees his sister-in-law masturbating. Captivated by the voluptuous charm of his sister-in-law, who stands in stark contrast to his slender wife, Chang-seok eventually engages in a secret affair with her behind his wifes back. However, as the saying goes, “a long tail gets stepped on”. Their clandestine rendezvous is eventually discovered by his wife, and the three of them find themselves stepping into a new world.