It's Gabriel's fourth year at Crookhaven School for Thieves, and it's the most challenging one yet. Along with mastering a new class - Lay of the Land - Upper Delinquents are supposed to start thinking about life after Crookhaven. Their schoolwork is beginning to have real world implications, and this year's Break-In challenge is set in an external location known to be impenetrable - the Impossible Fortress.
But the world outside their school grounds can be a dark and dangerous place. And with the most powerful crew in the underworld, infamously known as the Nameless, out to get Gabriel and his friends, the stakes have never been higher.
The crew need to put everything they've learned so far to the test outside of Crookhaven's gates. But there may be something lurking within those gates that the crew should be wary of too...