Onee-san To Ii Koto ♡

The volume includes the following chapters:

Over Drive (オーバー♡ドライブ, Over ❤ Drive); COMIC X-Eros #50
Over Charge (オーバー♡チャージ, Over Charge); COMIC X-Eros #61
Over Summer (オーバー♡サマー, Over Summer); COMIC X-Eros #67
Swimmy! (Swimmy！, Swimmy!); COMIC X-Eros #75
Isshoni Swimmy! (いっしょにSwimmy！, Swimmy Together!); COMIC X-Eros #79
Motto Swimmy! (もっとSwimmy！, More Swimmy!); COMIC X-Eros #83
Manabu Obocchama wa Shishunki (学お坊ちゃまは思春期, Master Manabu Has Hit Puberty); COMIC X-Eros #53
Himitsu no Jikan (ひみつのじかん, Secret Time); COMIC X-Eros #56