There is no goal in this movie, other than shuttling between musical numbers. Moreover, the musical numbers in the film are good, but lack the spontaneity that marked the first movie as a classic. The extras wear costumes rather than street clothes, and they dance on fake-looking sets instead of in realistic settings. Indeed, the only thing that makes the musical numbers good is the music. Blues Brothers 2000 meanders from number to number, with very little in the way of actual plot in between.
Nothing ties it together.
Either that, or a lot of stuff ended up on the cutting room floor. There is a battle of the bands at a voodoo palace at the end of the movie, and we guess this is supposed to be the goal. The last scene in the movie, which we will not give away, is sort of odd. The movie just peters out. The credits happen, and the audience figures that its time to go home.