Gwen has returned to Neverland with Peter Pan and the lost children, but this time, the adults are following close behind.

The Anomalous Activity Department has plans to finally conquer Neverland by bringing the final battle to the vulnerable island. The children will have to rally fairies, mermaids, and allies from other magical realms to stand a chance against the shadow-casting army of grown-ups heading for them.

The black-coat soldiers are far from their only problem. Lasiandra is missing. No one has seen her since Gwen left her at the lakeside with Jay, and the mermaids searching have found only grave omens in the stars. With the island on the cusp of a war that threatens to strip the land of its magic, the last thing Peter and Gwen need is the ancient flagship that appears on their horizon, sailing pirates straight for their shores.

When the battle begins amid old and new enemies, Gwen's maturity will be a double-edged sword. She will either grow stronger or grow up... maybe both.