They start as sex friend (at first they both top, so used to threesome w bottom at middle, but Gyuha got corious being fucked and they relationship changed).
Gyuha, an omega, but got pheromone induction treatment and poses like beta. Chaeyoung, an dominant alpha.
Chaeyoung didnt know Gyuha is an omega and they fuck wo condom, even ehen Chaeyoung has rut. Then tadaa~ the baby come. They have cat-mouse run tho, bc Chaeyoung said to get rid the baby (he didnt know the one who pregnant is Gyuha).