Love/Knot (Yaoi)

Keigo Someha, a private detective and assassin, finds himself nursing Emiya
Nozaki - who had an unbelievable, near-death experience right in front of
his house - back to health. Emiya knows virtually nothing about sex and
everyday life, thus Keigo feels that it is essential to shield him from the
world's perversions. Meanwhile, Hamuro becomes fixated when he discovers Emiya's
unique power, and he cunningly lures Emiya into a research institute!