Ghosthunters and the Gruesome Invincible Lightning Ghost!

After banishing the Incredibly Revolting Ghost of book 1, Tom, former klutz, Hugo, still an Averagely Spooky Ghost, and Hetty Hyssop, world-renowned ghosthunter, have formed an agency dedicated to dealing with difficult apparitions. No case can defeat them--until they encounter a Gruesome Invincible Lightning Ghost. This smoking specter has claimed the penthouse suite of a beachfront hotel, where it passes its eternal vacation by turning guests into ghosts themselves. Could Hugo's slime douse the flaming phantom--or are Tom and the team about to get burned?