A bowl of poison for the king

At a dinner with King Wenceslas IV. Duke Frederick of Bavaria was poisoned. The royal hofmister Jindřich Škopek of Dubá has no doubt that the cup of wine with poison was originally intended for the monarch himself. But who wanted to poison him and why? The answer to this is to be given by Jakub Protiva of Protivec, the New Town's town crier, and the Franciscan monk Blasius. Their successful solving of the cases of the Prague Ripper and the Horse Market Vampire predestined them for this task. But can they succeed this time? The threads of the plot against the king are very tangled indeed, but both honest men are determined to track down the poisoner at any cost.