The adventure continues for Niko and his friends as they face the invasion of the portal pets! With the gateway open and Bob's army rushing through, Niko must be ready for battle. Teaming up with his new friend Rhiannon, the pair must rescue their parents, and save the world from these strange, tentacled creatures. Will they have what it takes to defeat the invaders? Find out in Niko's Nightmare: Invasion of the Portal Pets, Book Two in the Niko's Nightmare series.