Les Pyjamasques et le Grogarou (English: The PJ Masks and the Big Werewolf) is the first book of Les Pyjamasques which was published by Éditions Gallimard on March 29, 2007.
It's midnight, Yoyo, Gluglu and Bibou are not in bed, they're out playing acrobats! But is it safe to go out at this hour? Do they know that when the moon is round, strange creatures roam in the dark and growl? "Not even scared, not even scared!" scream Les Pyjamasques. But what is this beast?
Les Pyjamasques fight the Grogarou that looks like a big nightmare and give small readers the feeling of being able to overcome their nocturnal anxieties.
Yoyo (first appearance)
Bibou (first appearance)
Gluglu (first appearance)
The book begins with Les Pyjamasques wandering through the night doing their acrobatics as the clock strikes at midnight.
Les Pyjamasques were interrupted by Grogarou who roared at their faces, but the heroes proclaimed that they are not afraid of him and retaliated by screaming at him which caused him to fall backwards with surprise. Then Les Pyjamasques started playing around with him, wondering who Grogarou is.
Angrily, Grogarou threw them off his back and reveals his plan that he is going to eat the heroes raw as stated that during the full moon he becomes a werewolf. With that, Les Pyjamasques try to evade pursuit from Grogarou, Bibou tries using her cape to trip Grogarou, but she is unfortunate as her cape was caught by the monster who attempts to eat her while protesting that he has school tomorrow. With bravery, Yoyo and Gluglu rush to Bibou's rescue by lunging at Grogarou, and this caused Bibou to break free from Grogarou and used her wings to cover the moon.
Due to the result, this caused Grogarou to shrink into Ptigarou. However, Les Pyjamasques prefers him to be at a "petite" format in which Ptigarou agreed proclaiming that he feels lighter.
At the rooftops in which Les Pyjamasques and Ptigarou met, the heroes decided to give him sunglasses as a gift. Though, this doesn't faze Ptigarou, but was happy that he can watch the moon without turning back into Grogarou. Yoyo asks Ptigarou that if he would had really eaten Les Pyjamasques raw, he disagreed and prefers to have the heroes cooked beforehand. As he took off his glasses, this caused the heroes to run for their lives.