It's June of their third year of high school, and Takumi has an important anniversary to attend back in his hometown. He wants to invite Gii along for the trip, but time and scheduling and possibly broken promises stand in the way.
Unlike the three previous films, Pure focuses on the relationship between Misu Arata and Shingyouji Kanemitsu , which begins when Shingyouji takes the test to enter Shidou Gakuen . That's when he meets Misu and falls for him. Then we come back to the present where the sempai who admires Misu appears, bringing Shingyouji problems and jealousy.