Ruka-san, Kiki Ippatsu!!?

After reluctantly agreeing to go out on a hiking trip with fellow university classmate Murase, Ruka's "date" takes a turn for the worst when a raging downpour throws a wrench in their plans and forces them to seek shelter in a nearby cave. But Ruka soon starts feeling hungry and finds a suspiciously quiet Murase munching on a chocolate candy bar. Unfortunately for her, however, Murase is unwilling to share—unless Ruka shows him her breasts.