If a stranger dropped a horribly ugly goblet on your doorstep, would you drink from it? Or, more importantly, should you?

The answer, of course, is no. But Barnabas Tew has no use for rules, unless they are of his own making.

Freshly returned to London as a reward from Aphrodite, Barnabas and his business partner, Wilfred, are enjoying a nice supper with their lady loves, Bindi and Brynhild, when the doorbell rings. Someone has deposited a box on their doorstep, and within is a cup that is as old as it is large. Everyone agrees that Barnabas should leave it alone, but he never listens. Not only does he drink from the hideous vessel, but he also convinces Wilfred to do the same.

Right away, it becomes obvious that this was a mistake. The unwanted gift is not just any goblet; it is the mythical Holy Grail! And it whisks Barnabas and Wilfred off to Camelot of yore.

So begins Barnabas’ strangest adventure yet. Tasked by King Arthur himself, Barnabas and Wilfred must find the Grail again and bring it back to Camelot – or die trying. Meanwhile in London, Bindi and Brynhild have their own troubles. They track down the not-so-benevolent benefactor who gifted them the Grail to try to figure out not only where Barnabas and Wilfred have been sent, but also why.

Knights and fairies, wizards and witches, curses and promises – all of these are at odds in Camelot, and all have their own agenda. But which are friend, and which are foe?