Cameraman Charlie Hamilton James has filmed otters more than anyone else and now, through the eyes of three orphaned river otters, he reveals their survival secrets.

Otters are playful, adaptable and champion swimmers - they've captivated cameraman Charlie Hamilton James for the last 25 years. He's filmed them more than anyone else and now, through the eyes of three orphaned river otters, a set of groundbreaking experiments and some incredible wild encounters, Charlie wants to reveal their survival secrets and exactly why he believes they're so special.