Overview:
The main character is trapped in an uninhabited hot spring inn with a junior who has big tits and is the only one who can perform paizuri.
Not only that, but she is not even allowed to enter the hot spring.
She has no choice but to wander around the ryokan to find out the cause.
Since the junior boob always follows him around, he can talk to her and get a titjob wherever he wants.
Since you are at a hot spring ryokan, by all means, aim to make love to your lover's tits in the hot spring.