Mo never wanted to be a Warden - protecting the village of Bogfoss from the terrifying monsters in the woods is way too scary. But when he's beaten up by a goblin on his first patrol, he knows he has to prove himself. So he sets out into the forbidden woods to catch himself a monster and make himself a hero. But when a sausage roll-baited booby trap flips him into Grumpfort, the monsters’ secret lair, he realises he’s in big, BIG trouble. Mo’s escape plan is simple – capture a monster, avoid being eaten, and do not make any friends. But there is something dark dwelling at the heart of Grumpfort, something even the monsters are scared of – and suddenly Mo finds himself teaming up with a troll, a gnome and a fire-breathing snotwoggle to catch the most terrifying and mysterious monster he’s never heard of…