Doctor Who: Short Trips Monthly is a series of new short stories read by an original cast member. Release #3 is a Third Doctor, Jo and UNIT story. Reports are coming in to UNIT of trains emerging from a railway tunnel in Sussex, their passengers and drivers dead. The Doctor elects to drive a train through the tunnel himself, but when he emerges Jo sees to her horror that he is covered in ice. Something in the tunnel has driven him close to the point of death. What can it be?