Iolo Williams showcases animals that use intelligence to survive the challenges of winter. He begins on Anglesey, where he joins raven expert Nigel Brown to investigate these highly intelligent birds, using thermal imagery to uncover the secrets of their night-time activities. Ravens are highly social and raucous as they gather to roost and share information about where food can be found – vital when resources are scarce. While ravens are masterminds of the air, beneath the waves, a curled octopus is on the hunt - but will this cunning creature be outwitted by a crafty cuttlefish?