My Youth Romantic Comedy Is Wrong, As I Expected @ comic, Vol. 18 (manga)

Full steam ahead toward prom! The Soubu High School Prom is at a standstill now that
Yukino's mother is on the scene. Seeing how much Yukino and Iroha want to hold the
event, Hachiman plans a separate prom of his own—a move that’ll inevitably lead to
conflict with both girls, and will require asking for help from others. Yui has a question
for Hachiman: Just what is he thinking....?