Olly Spellmaker and the Sulky Smudge

Olly has a problem and she wants Alex's help. Her beloved motorbike is off the road and she needs to earn some money to repair it. She's been offered money to find some ghosts for an old pub that doesn't have any. Does Alex know where Olly can find some ghosts?

Alex tells her about the ghost that haunted his old school, and the ghost that haunts the canal tow-path, and the problem seems solved. But then the sulky Smudge turns up, which isn't what it seems...