A call from an old colleague has DI Adams off her patch and out of her depth, dealing with a mysterious new beer that has unexpected side effects. Side effects that are much more dangerous and far-reaching than a simple hangover. Missing brewers. Inexplicable superpowers. Erratic behaviour. And it's not just the punters. Half the police in Yorkshire seem to have fallen under the beer's spell, and she's barely keeping a step ahead of them. If she doesn't figure this out before the festival opening night the whole county will be under the influence of Niddered Ale, and there'll be no sobering up from it. Not ever. But she's got her invisible dog, her inanimate duck, and some unusual sidekicks. Plus she's just dying to arrest someone. As soon as she can catch them, of course. . .