Don't Call it Mystery Manga Omnibus Volume 6 collects volumes 11-12 and features story and art by Yumi Tamura.

At his classmate's suggestion, Totonou signs up for a “sketchy” part-time job. Meanwhile, as Garo and his crew continue the search for the truth behind his sister's murder, they find themselves hot on the heels of her therapist, Naruko. Is the doctor somehow responsible for what happened to Naruko? And if so, how far will Garo go for revenge?