Sora no Otoshimono Forte

Synopsis

Winter comes to the city, and Astraea is still far from completing her mission of eliminating Tomoki. Mikako reels her into another of her sadistic schemes, staging a snowball battle between the girls and boys of her school, with the rule that you can still battle if you get hit and until the commander, Mikako versus Tomoki, loses. The winners get to boss around the losers for a day. While Mikako steps aside, taking Ikaros and Nymph, to search for a hot springs, Tomoki and the boys stage an assault on the strongest girl on the team, which is not Astraea but Sohara. At dusk, while the surviving girls relax at the hot springs, the boys appear to have the advantage, until the popular boys rebel by freeing the captured girls, and Tomoki's team must face the wrath of the "Abominable Snow-hara Man". When Tomoki get stuck in the snow, Astraea has her chance to take out Tomoki, but Ikaros arrives to prevent that from happening. The next day, Sugata comments how Astraea is not allowed to return to Synapse until she kills Tomoki, something he pities on her about.

(Source: Wikipedia)