One thousand years after cataclysmic events forced humanity's escape from Earth, Nova Prime has become mankind's new home. Legendary General Cypher Raige returns from an extended tour of duty to his estranged family, ready to be a father to his 13-year-old son, Kitai. When an asteroid storm damages Cypher and Kitai's craft, they crash-land on a now unfamiliar and dangerous Earth. As his father lies dying in the cockpit, Kitai must trek across the hostile terrain to recover their rescue beacon. His whole life, Kitai has wanted nothing more than to be a soldier like his father. Today, he gets his chance.

The fourth series begins with the nation’s favourite detective, the mercurial Sherlock Holmes, back once more on British soil, as Doctor Watson and his wife, Mary, prepare for their biggest ever challenge - becoming parents for the first time.