As the Sandman, Sam has spent millennia dedicating his existence to bringing hope to others. His only chance for sight being found in reviewing the past or in dreams, which often leaves him the voice of reason within the Keepers. After multiple attacks from an enemy, Sam reconciles with the fact his only chance to be with his mate safely is in the dream world or not at all.
Whyte, the Tooth Fairy, has witnessed his twin and friends suffer through personal attacks after claiming their mates, and understands where his mate's concern is coming from. He just never realized accepting Sam's terms would be so difficult.
When the Keepers get closer to the ones responsible for all the harm they have faced, they realize the board has more players than they originally thought, and in order to come out on top, they may just have to make a deal with the devils.