The author, actor and comedian embarks on a journey through the entire Central American isthmus to the Panamanian border with South America, beginning in Mexico. Stephen tours the country in his yellow American school bus, takes part in a soap opera in Mexico City and heads for the Pacific coast, where he is entranced by the magical migration of the Monarch butterfly and the courage of cliff divers in Acapulco.

Stephen travels through Belize, the only former British colony in Central America, bottle-feeding injured manatees, hearing the music of the Garifuna people and meeting a reformed drug addict living 40 miles off the mainland on the Turneffe Flats. On arrival in Guatemala, he learns to weave with the Mayan people and teams up with an ex-Miss Guatemala on the banks of Lake Atitlan, before a night patrol with a volunteer heart surgeon.

Stephen travels to El Salvador and Honduras, two of Central America's most dangerous countries, ridden with gangs and drug cartels. However, El Salvador also has some of the best waves in the Americas, and the presenter is soon persuaded to try his hand at surfing. Moving on to Honduras, he visits a banana plantation where new varieties are being developed and meets a woman convicted of killing and cooking six of her husbands, before stepping over the border into Nicaragua for a visit to a cigar factory and to learn how to dance the maypole.

Stephen's travels continue in Costa Rica, where he encounters poison-dart frogs and falls in love with a baby sloth at a biological research station. But he soon finds there is more to the country than conservation and eco-tourism as he ascends volcanoes, descends white-water rivers and experiences the passion of a football derby in the capital of San Jose. He then crosses over into Panama for the final leg of his trip, witnessing giant leatherback turtles coming ashore to lay their eggs and learning how to dredge the canal in Panama City.