Helgoland, 2039: A child is born. Because the island is sealed off from the outside world due to a pandemic, no more than 513 residents are tolerated. Who has to die?

Linus, son of island doctor Marek, volunteers for a dangerous mission on the mainland. Meanwhile, an alarm goes off in the water treatment plant.

After returning from the mainland, a resident succumbs to the virus, whereupon island boss Beatrice looks for the culprit. Marek is researching an antidote because Linus is also infected.