Koga is omega who was raped by his classmate Alpha and got pregnant. Deu to his trumatruma he decided the he does not need lifetime partner nor bond ,but even what happened he kept the child and decided to raise himself .his baby girl an angel named shizuku
She became his reason to love but then his life sudden changes when he meets his fated pair
Rika got raped in high school and top of that he got Bitten also by someone whose face Rika doesn't even remember because of that he can't have sex with anyone his body aches to hide that fact he pretends to be Alpha in uni. And his life was quite peaceful. Then when Rika was in heat was saved by someone who is also happens to be his mate then his little world changes little by little.
Kyou Kara Omega ni Narimashita