Mission: Yozakura Family, Vol. 5 (manga)

To find out more information about his deceased parents, Taiyo visits the Library of the Dead. This library is infamous for its strange director, who murders anyone who makes so much as a peep in her domain! While there, he finds out that an organization known as Tanpopo was involved in his family’s deaths. But the documents self-destruct while Taiyo is still insid the library - and that’s way more than just a peep! Later, Taiyo and Mutsumi attempt to infiltrate a hospital known to have connections with Tanpopo, but a doctor there named Kawashita is already one step ahead of them...