David Ridersson has taken on the Debt, the moral obligation that requires him to deliver all of the parcels of his friend's last consignment. He has sworn to finish this task before Moon Watch Night regardless of the interference of murderous Doppelgangers, amorous Fenodyree, conspiring wizards, or bloodthirsty Druids.
If he fails, magic as he knows it might come to an end.
Or, if he succeeds, magic as he knows it might come to an end.