The Wicked Isle story expansion is set on Midsummer Island. To get there, players must speak to the boat-keeper in Wyndham Village, who provides the first Lead.

Located near the Windscale Atom Plant, Midsummer has higher infection levels and introduces new enemies like pirate bandits and infected druids. Players can find new weapons, including a Blunderbuss, bow, daggers, the Beekeeper’s Staff, unlock new skills and an upgraded metal detector.

Leads found on the island open new story paths and possible alternate endings to Atomfall.