Funky Lupin III flick. The overall quality of these films is pretty consistent, even though the technical qualities and plot influences can vary quite a bit between different entries. The quirky characters, the unflinching focus on fun and the freedom to go to a little mad from time to time are what defines these films.
The Mystery of Mamo has one of those larger than life plots that are quite prevalent in anime. It starts with Lupin stealing the Philosopher's Stone, but before he knows it he's dealing with a crazy adversary who is trying to collect all the great minds that ever lived. Apparently that includes Fujiko. Just another day in the life of the master thief.
The art style is pretty cool, the animation is well over the top and the pacing is quite crazy. By the end, I felt I'd watched three separate Lupin III films rolled into one. Not that I'm complaining, I like these zany films that start in 6th gear and don't slow down, but it's probably not the best entry in the genre for those unfamiliar with the Lupin III franchise. Good fun.