Rentaro's never had an easy time appeasing his twenty-two-and-counting girlfriends. One's eternally hungry, another adores violence, and another secretly wants to be treated like a baby. But when he locks eyes with a twenty-third lover who's so in love with numbers that there's little room left in her heart for anything else, what's the world's best boyfriend to do? Meanwhile, the family goes night swimming, ventures on a fluffy obstacle course, and pairs off for some girlfriend-on-girlfriend bonding!