During the destruction of the Hosnian system, Finn is a young senator was out of the system and is technically now the chancellor of the New Republic, as everyone above him in command was killed.

The Resistance needs to get him safely to the new capital of the Republic. The First Order is, of course, hunting him to blackmail or re-condition him into undermining the new government.

Poe is tasked with escorting the Chancellor, in absolute secret, to the safe planet. Things begin to go wrong very quickly.