After a secret mission in Afghanistan ends in a terrible accident, Raja Roychowdhury, fondly known as Kakababu, resigns as the director of the Archaeological Survey of India and goes home to his second-hand books. But the desire to hunt down old, unsolved mysteries of the world refuses to leave him alone. Despite living with an amputated leg, Kakababu insists on taking biannual holidays to remote, little-known areas - and refuses to tell anyone what he does there. Now that he's old enough, Shontu, Kakababu's nephew, has finally been allowed to accompany Kakababu on these mysterious trips. And he cannot wait for the thrilling adventures to begin! In 'The Emperor's Lost Head', Kakababu takes Shontu to Kashmir to find a hidden sulphur mine. Except that that's a lie, and Shontu has no idea how to get his uncle to admit the truth. 'The King of the Emerald Isles' finds uncle and nephew in an uncharted island in the Indian Ocean. Stubbornly secretive as always, Kakababu refuses to tell Shontu what has brought him to the dangerous island. Is he ready for the answers he might find?