Nico meets Dr. Saltzman (the principle) to make a deal: he helps her find her cousin, and in return he will help his daughters live. But Nico needs a sacred book owned by the Mikaelson family. Nico is part of that family, but is only known to be apart of the Parks. At first he declines, but soon accepts, though they realise the book is actually missing.
Nico, Hope, and Josie, go to get the book, at a lab that contains mystical creatures, one that was awaken, and attacked them. His name was Malavor a servant of Mallus. After a long battle, Malavor is defeated, leaving Hope and Josie wondering why Nico is really here in Mystic Falls.
Nico explains why she's actually there, while reuniting again with Penelope, after not seeing her for 5 years. Here Penelope absorbs the magic of the book, with Josie. Then they all prepare to fight Mallus, ending him once and for all.
They all fight off Mallus in an extreme battle. Here Damian, Mallus's brother appears to help Nico, and Skyler, Nico's diseased sister, is summoned to fight along Nico. Penelope and Josie distract Mallus throwing him off, while Hope, Rick, Caleb, and MJ fight off Mallus's army. Nico and Skyler then finish off Mallus together, destroying him, and his army that came with him.
Nico assure Rick of how to stop the merge happening that will kill his daughters. She also gives him, as well as the others each rings that if pressed Nico will be summoned, this would be for emergency purposes. Nico also puts extra protection over the school, so no monsters/demons will be able to attack it.
Nico and Penelope catch up, and Nico trains Penelope how to use her power, like Nico was suppose to do years ago. Nico also brings along Hope to talk to the two of them about safety, and family pasts and secrets. Then Nico takes her leave, because she still has unfinished business that needs to be resolved. The story ends with the school safe, and no danger. For now.