Dougal and the Blue Cat (French: Pollux et le Chat Bleu) is a 1970 animated film based on The Magic Roundabout directed by Serge Danot.

[1] One morning in the magic garden, after a rude awakening from his cuckoo clock, Dougal the dog remembers a strange event that happened the night before.

Dougal recounts how, after being awoken and greeted by a strange red owl, he had heard two voices coming from the old treacle factory that had been shut down.

At the roundabout, Florence is greeted by Mr. Rusty and the other kids who show her a surprise: a sly blue cat, who introduces himself as Buxton.

As she takes him to the bridge to meet the other animals, Dougal becomes jealous of the attention directed toward Buxton, and suspicious that the blue cat's arrival might be related to the strange event from the previous night.

Back at the garden, the gang finds Dougal, having been previously stuck from an elevated platform, who tries to warn everyone that Buxton is evil.

Dougal takes a "tour" of the caves beneath the treacle factory, and manages to locate his friends in the dungeon, only to be followed by Buxton.

When Dougal tells the gang what happened to Brian, they all mourn for their friend, causing Buxton to "blush for shame", revealing his true colour to be white.

There was also another storybook adaptation released around the same time by Dean and Sons, which was a different, more kid-friendly retelling of the story with very little resemblance to the original film.

[2] This release by Second Sight also features the original French version of the film Pollux et le Chat Bleu, interviews with Fenella Fielding, Phyllida Law and Emma Thompson, an overview by film critic Mark Kermode and a photo gallery featuring the original cinema lobby cards of the French release.