A letter arrives at Nest Cottage, warning of danger for all former companions of the Doctor. Intrigued, Mrs Wibbsey begins a correspondence with one Polly Wright - and soon finds herself with an unexpected guest for Christmas. But shadows are gathering in the Hexford snow, and old scores are waiting to be settled. With Mike Yates and other friends around her, Mrs Wibbsey must navigate her way between facts and half-truths if she's to keep the Doctor's secrets safe, and live to tell the tale...