Life carries on for Arthur (Freddie Highmore) who spends his holidays at his grandparents and much of his time with the Bogo Matassalai who live in his grandfather's shed. But just as his parents are about to leave with Arthur to return home a spider comes with a message on a grain of rice for him from the Minimoys who need his help. With the help of the Bogo Matassalai Arthur shrinks down to the size of a Minimoy and heads back to their world where he meets up with Selenia who is mystified as she never sent the SOS message. It is then that the evil Maltazard reveals that he sent the message whilst taking Selenia hostage as he is still angry about being beaten by Arthur before and now wants world domination.
I was not overly fussed by the first "Arthur and the Invisibles" movie as I found the whole adventure of little people being old hat but thought for young people it probably worked. But I must admit I was surprised when a sequel was made because when you have entered the world of the Minimoy once what else can be achieved by returning back other than repeating the story of the little people in danger and Arthur coming to their rescue. And that for the most is what you get, with Arthur having to deal with Maltazard again although Besson gives us a vice versa situation as those from the Minimoy world find a way to enter the human world and at full size.
What this really means is that "Arthur and the Great Adventure" begins to feel little more than an outlet for Luc Besson's imagination as we meet more strange characters and see more imaginative gadgets in the land of the Minimoy. But for me Besson's imagination is not enough to sustain my interest and makes watching this 2nd movie a bit of a chore. It is also a chore when you get to the abrupt end and know that if you want closure you will have to sit through the third movie.
What this all boils down to is that again "Arthur and the Great Adventure" is a movie which might entertain young children because of the look and creativity when it comes to the Minimoy but it isn't something which is going to keep an adult entertained at the same time despite the fact it has some elements which might scare a young child.