Courage the Cowardly Dog revolves around the exploits of Courage, a small, fuchsia dog who, despite his name, is afraid of the most mundane things. His fears are normally justified, however, as Eustace, Muriel, and Courage are constantly attacked by (or running into) various monsters, aliens, villains, curses, experiments, natural disasters, and other forms of peril that Courage must face.
Every opening of the show documents Courage's past: "Abandoned as a pup, he was found by Muriel, who lives in the middle of Nowhere with her husband Eustace Bagge. But creepy stuff happens in Nowhere; it's up to Courage to save his new home."
In the series, when Courage wants to save his family from the villain, instead of typical feats of strength, the villain is usually defeated in a variety of many other ways: Courage tricks the villain, he flees from them, makes amends with the villain, somehow convinces the villain to change, Muriel saves the day, or in some cases, the villain simply voluntarily moves on in favor of plotting another diabolical scheme. Ironically, Courage exhibits no courage whatsoever. Almost every single event that happens to him causes him to scream manically and usually shape-shift into some random object that portrays fear, sorrow, confusion, or some other random emotion.
A typical feature of the show is the spoofing or reference of various classic horror and cult films as the basis for many episodes. This is seen in episodes such as "The Demon in the Mattress", "The Precious, Wonderful, Adorable, Loveable Duckling", "Heads of Beef", "Klub Katz", "Night of the Weremole", "Journey to the Center of Nowhere", "The Great Fusilli", "Robot Randy", "1000 Years of Courage", "Invisible Muriel", "Human Habitrail", "Courage the Fly", "Mega Muriel the Magnificent", "The Transplant", "McPhearson Phantom", "The House of Discontent", "Courage vs. Mecha-Courage" and "Hard Drive Courage".
La trama de la serie está planteada en el poblado de Ningún Lugar, en Kansas. Coraje vive con sus dueños, Muriel y Justino Bolsa. Muriel adoptó a Coraje cuando era un cachorro, y cuando algo le ha pasado a Muriel o Justo, Coraje va a rescatarlos como agradecimiento a Muriel por su hospitalidad y cariño. Pero Coraje se ha visto en las situaciones más extrañas que uno se puede imaginar.