Everyone in Iceland has heard of Gudmunder and Geirfinnur. They were two (unrelated) men who disappeared in 1974, albeit ten months and several miles apart. Gudmunder Einarsson was a teenage labourer who loved to arm-wrestle; Geirfinnur Einarsson a construction worker and family man. Other than shared national hysteria in a country where people rarely go missing, there was nothing to link these mysteries — until, one by one, a ragtag group of petty criminals started to confess to their murders.