1941. Casablanca. Murder. Sound familiar? It does as well to the Doctor, Amy and Rory, who revel in being in the setting for the classic film. That is until they discover a world-domination plot hatched not by Hitler, but the Silurians!
The police arrests a man in the café, who later dies in custody at the hand of Silurians masquerading as policemen. In the film, the police arrests Signor Ugarte in Rick's Café Américain, who later dies in custody because of apparent foul play bu the local police.
The Eleventh Doctor observes how the café owner hears the pianist playing "As Time Goes By" from behind the doors and storms in to remind him never to play it. In the film, Rick hears Sam playing "As Time Goes By" from behind the doors and storms in to remind him never to play it, only to find Ilsa there.
The Doctor helps the woman get into the closed café, where the pianist is playing for the owner. In the film, Ilsa sneaks into the closed café, where Sam is playing "As Time Goes By" for Rick.
At the end of the comic story, Silurians make it rain in Casablanca. At the end of the film, it rains in Casablanca.
The Doctor asks the Captain to sing "La Marseillaise". In the film, Victor Laszlo leads French nationals in singing "La Marseillaise" to drown a German song by Nazis.
The Captain and the café owner see the plane off while a dead Nazi lies nearby. In the film, Captain Renault and Rick see the plane with Victor Laszlo and Ilsa off while the body of Major Strasser lies nearby.
One of the last phrases of the comic story, "This is the end of a very terrible vacation" is an homage to the last phrase of the movie, "This is the beginning of a beautiful friendship."
However, there are also deviations. For instance, the café owner, the Resistance leader and the woman are shown in the comic walking towards the airport by themselves, while the Captain is still under arrest, whereas in the film Captain Louis Renault waits for them in Rick's café, and all four travel to the airport together. Despite these minor deviations, it is not hard to combine the film and the comic story into one continuous narrative.