The children of Twigswick are taught three things:

1. Never stray past the rune posts at the edge of town
2. Run home as fast as you can when the warning bell chimes
3. Spirits are very real andverydangerous

Nettle Sourbudlives in the shadow of her older sister,Fern; fearless, tough and confident, Fern is everything Nettle is not.

So, when Fern runs off to join theWildheart Rangers– the protectors of towns from the spirits and ghouls ofDryda Forest– Nettle thinks shes lost her sister forever, as shell never be brave enough to follow her into the enchanted woods.

Then news reaches Twigswick that Fern has abandoned the Rangers to join the infamousShadow Stalkersand Nettle knows something isnt right. Fearing her sister is in danger, she ventures into the forest to find the truth . . .

Joining the Rangers, Nettle realises shell have to face her fears and defeat theHollow Spiritswho haunt the forest if she wants to rescue Fern.But soon Nettle starts to wonder if her sister needs saving at all, or Fern is the one who must be stopped . . .