Isham Seely is a Survivor in the Sonaran Desert. Formerly a pharmacist in Sienna along with his friend Charley Pankhurst, he was saddened when she disappeared, but he managed to begin to live comfortably in Sienna. However, when things were starting to take a turn for the worse, Isham decided to join up with Joe Wheeler and Alice Ivers; forming the only three characters in the Sonaran that are guaranteed to join the Survivalists at some point.

Once Isham settles into life at the bunker, he begins to build defences and lodgings and sources of nutrients all around, setting up a sustainable and virtually impregnable base for the Survivalists to live in.

Isham, now well-equipped, is eager to search for Charley and be happy again. The Survivalists find a F.E.M.A. convoy that was besieged by Red Strains, and they find a brain scanner. Later on, when the group storms F.E.M.A., they find Charley in a cell. The Survivalists reunite her with Isham, and all is well; until it's revealed she's a Living Infected, and she is put down. Isham is sad, but decides to push on and just keep going.

Eventually, he gets his wish, and leaves alongside Joe Wheeler to find Alice Ivers in Vancouver.