Shinoda Yu (MIAE-240) becomes invisible while spying on his wife's affair until he gets an erection.

One day, suspecting his wife of infidelity, he's chosen as a test subject for a drug that makes him invisible. With this drug in front of you, what would you do? Become invisible to spy on her? Even though you desperately don't want to see your wife cheating, you can't resist getting an erection!