The Reckless Afterlife of Harriet Stoker by Lauren James

"Congratulations, new kid. 
Welcome to the afterlife."

When Harriet Stoker dies after falling from a balcony in a long-abandoned building, she discovers a group of ghosts, each with a special power.

Felix, Kasper, Rima and Leah welcome Harriet into their world, eager to make friends with the new arrival after decades alone. Yet Harriet is more interested in unleashing her own power, even if it means destroying everyone around her. But when all of eternity is at stake, the afterlife can be a dangerous place to make an enemy.