The actor and his son embark a 3,000-mile journey through Europe, aiming to experience extremes from the fiery heat of the Mediterranean to the icy tundras of the Arctic Circle. They begin in Croatia, where they swing off the roof of Hajduk Split's football stadium, before diving headfirst into the crystal-clear waters of the Adriatic. The action continues when the pair go head-to-head on aqua bikes alongside a former world champion, before heading to the capital Zagreb to meet a young inventor, who stuns them with his electric creation.