Vol. 1: Egao no Ura ni wa Vol. 2: Yasashi sa no Ura niwaVol. 3: Himegoto no Ura ni waVol. 4: Hatsukoi no Ura ni waVol. 5: Dekiai no Ura ni wa

1-3) A Gentle Depression (Yawaraka na Yuuutsu) 3.5) Satou Nao's Troubles When The Stars FallWe'll Have To Be Together

Koki Orito slept with his best friend's older brother, Mitsuru! It all started when he ran into Mitsuru at his mom's bar where he works... the same bar Mitsuru was using for drinks with business clients...