Dara O Briain and the team go on a journey through time to discover what it is and how to get more of it.

Dr Helen Czerski witnesses the most incredible recreation of a living, beating human heart that has been grown in a laboratory.

Alok Jha investigates the tiny margins of winning as he examines the multi-million pound technology behind the British bobsled team's push for Olympic glory.

In the studio Professor Mark Miodownik slows down time to reveal the mysteries of explosions, solves a centuries old puzzle and shows how to see light itself.

The team also have an encounter with some time-travelling rats, explore the missing piece in the history of the universe (the mysteriously named cosmic dark ages) and discover how bats might hold the secret to us all living longer. Show less