What happens 3 years after Allegiant. Told from the perspective of Tobias, (Christina a little), and someone else you'll later meet (or reunite with

'Pain isn't remotely kind in that way. Pain wants its promised pound of flesh, ounce for ounce. It won't settle until you're left with nothing but a flaky shell of who you were. The burn of betrayal and the sting of rejection hurt, but nothing compares to the pain of being empty. Nothing hurts worse than not hurting at all and it makes no sense and perfect sense at the same time and I'm convinced I'm going crazy and I'm actually okay with that.'