Set in noughties Britain, Mouth to Mouth deals with six young adults as they enter their twenties and realise that there is more to status than a Facebook update. Each year-in-the-life episode concentrates on one character's story as their lives intertwine and sometimes collide. Small events have big effects and molehills become mountains, as each of them scrabble to find their way and discover that be it comic, tragic and unpredictable, modern life can be tough.