Rise of the Nightmares (Jelsa/The Big Five)

When seventeen-year-old Elsa Arens heads out to the Ballroom Club a few days before her eighteenth birthday, she least expected to witness four teenagers murder someone in a janitor's closet. When they find out she can see them, they're just as confused as her.

Elsa knows she should report it to the police but when there's no evidence of a body, and no one can see the murderers but her, it's hard to explain to anyone what she saw. Keeping the information of that night to herself, she tries hard to forget about the four mysterious teenagers in black. But when Elsa's sister goes missing, they might be the only people who can help find her.

Disclaimer
All the characters belong to Disney and/or Dreamworks.
Some of the ideas for the plot came from The Mortal Instruments: City of Bones by Cassandra Clare, Walt Disney animated feature films, and Dreamworks animated feature films.