It is the omegaverse.

1% of the population is either an Alpha, or an Omega. When Alpha and Omegas come into heat they will seek each other out to breed, they cannot resist the urge.

But science has produced inhibitors that prevent this from happening. You are an Omega, and you feel your cycle coming on. You go to your room but find your inhibitors missing. You begin searching desperately.

"Looking for these?" You spin around. Lieutenant Simon Ghost Riley stands in the door way, Alpha.