Simple math. Minus= to take away. Easy enough in equation, in theory. Yet when Smokefang finds himself minus Sablefrost's warmth, her dry humour, her love, it is not an easy weight to bear. Comprehension still eludes him. He was doing his job, like any normal PureClan tom. Duty. Keeping up appearances, so the both of them don't get killed. Sablefrost can't seem to understand- does she not do her job? Does she not practice her duty? Her pair is the leader's son, and she is one step from death.
Sablefrost moves into the nursery, and it then a matter of addition.