My girlfriend, Mitsuki, found out about my cuckold fetish. A few days later, Mitsuki sent me a cuckold video letter. I thought cuckolding was just something to enjoy in fiction, but... watching the video of my beloved girlfriend and a strange old man making out with pleasure, my penis started to get hard as a rock. Mitsuki, who was cuckolded for my sake, also gradually became addicted to the old man's techniques...