Alpha!Booker and Omega!Nicky have been pining for each other for years but trying to hide their feelings from one another and the whole group (and Nicky using suppressants for heats, pretending to be a beta maybe and also maybe Andy is the only one who knows that he's an omega) until one unexpected heat while he is outside (at a party/bar) then Booker finds him, realizes Nicky is an unbonded omega, and all their feelings pour out. Booker takes Nicky home so from there, angst turns to smut and fluff. Nicky ends up being Booker's mate.

Bonus: Booker being protective and dominant at the party/bar when other alphas try to flirt with Nicky