Davos has been held prisoner at Manderley's castle in White Harbour for over two weeks. His ride home has long since sailed.
Manderley finally agrees to see him. Davos tries to appeal to Manderley's sense of honour to stick with supporting Stannis because he is Robert Baratheon's true heir, but Manderley knows a losing side when he sees one. The Freys try to claim that Robb caused the red wedding by turning into a wolf. Manderley knows this is nonsense but is going along with it anyway. Being on the winning side is more importance than truth!
Manderley's daughter Wyllis can see through all this and calls him out on it. She is young enough to be honest. But it doesn't do any good.
Manderley gets annoyed and sends Davos off to be beheaded as a traitor. It doesn't look like he is going to miraculously suvive after all.