Not to be confused with the manga, Prisoner (Kaen).
[From Fushichou]:
After Kei Oosawa’s father died in an car accident, all he had left was his father’s dear friend, Kazuma Takashina. Kazuma, who was still young, took Kei in and gave him a new home. During the years that passed by, a relation of desperation and hate grew out between Kei and Kazuma and the older Kei became, the more he wanted to escape from his ’prison’. Will Kei be able to live on his own, to escape from Kazuma...?