After breaking the enigma, Alan Turing and his team discover that there will be an attack on a British passenger convoy, and hundreds of civilian lives are at risk. Hugh starts calling Commander Denniston's office to let him know of the attack, but Turing stops him. Turing's rationale is that it will alert the Germans that they've broken the enigma. Their biggest challenge now is keeping secret the fact that they broke the enigma.
Although Zombies are terrorizing the world in pursuit of the brownies Billy made with Grim's ingredient, Grim keeps this a secret and doesn't allow anyone to touch his brownies, despite seeing the mayhem the zombies are causing.