Sisters Kat and Jo realise there's a zombie apocalypse in Birmingham, but gamer Kat has a plan: zombies can't swim - water is the safest option, and narrowboats move just marginally faster than zombies. Jo is unconvinced, until the guy she just slept with (Jude) turns into a zombie!

Meanwhile, Amar and Sunny have been in Birmingham for a stag. When all trains back to London are cancelled and they're attacked by a train guard zombie, they flee.

Kat and Jo narrowly escape zombie Jude and set sail on Dorothy (Jo's ex-boyfriend's narrowboat). Unbeknownst to them, Sunny and Amar are hidden in the boat's toilet!