Cal McGill is an Edinburgh-based oceanographer, environmentalist and one-of-a-kind investigator. Using his knowledge of the waves - ocean currents, prevailing winds, shipping records - McGill can track where objects have come from, or where they've gone. It's a unique skill that can help solve all sorts of mysteries.

Mark Douglas-Home is a journalist turned author, who was editor of the Herald and the Sunday Times Scotland. His career in journalism began as a student in South Africa where he edited the newspaper at the University of the Witwatersrand, Johannesburg. After the apartheid government banned a number of editions, he was deported from the country. He is married with two children and lives in Edinburgh.