Operation Houtou (Houtou Chouri Daisakusen, ほうとう調理大作戦) is the seventh episode of the Heya CampΔ anime.
Nadeshiko has lost her stamp rally booklet. The girls go back to the riverbed site of the fire festival, which is where she used it last, but can't find it there.
To take Nadeshiko's mind off of it and cheer everyone up, Chiaki gets the others to help her cook houtou.
Rin's grandfather has come to town on his motorcycle. He discovers the stamp rally booklet at the side of the road and takes it with him.