Explorers is a film that hits every single note exactly right during the first two acts, and then misses a beat in the third.

The film opens with the main character, Ben (Ethan Hawk), in the midst of a dream that has him flying over a vast circuit board. He wakes up and begins furiously scribbling what he can remember. Ben later takes his drawing to his friend, Wolfgang (River Phoenix), who is impressed that the diagram looks like it could actually be something.

Ben and Wolfgang aren't your average kids, as evidenced by their massive collection of Robert Heinlein, Jules Vern and H. G. Welles novels. Wolfgang's family is a strange picture of what might happen if the Mad Scientist decided to experiment not on dead bodies in dark castles, but instead on raising a family in suburbia.

Wolfgang, complete in white lab coat, decides to try to build Ben's diagram. The result is a machine that creates an impenatrable force field that is able to travel anywhere based on coordinates entered into a computer -- including right through solid objects.

The boys discover that they can make the force field as big as they want, including big enough to ride in. Ben and Wolfgang, along with a third boy, Darren (Jason Presson), come up with a brilliant idea: Since the force field is air tight, they should build a ship to fit inside it so they can fly around.

Soon, all three boys are dreaming of a new addition to the circuit board and they awake with plans to allow them to breathe inside the ship. It becomes apparent to them that the dreams are messages from some alien life form and the force field is an invitation to come visit.

Everything that happens in Explorers up to this point is pure magic. The boys seem like real and intelligent kids and the notion of the force field is handled with just the right touch, making the absurd idea seem plausible. In fact, the movie is so good up to this point that what happens once the boys get into space is all the more disappointing.

The setup is so filled with wonder that the actual alien encounter is shockingly disjointed. It's as though the third act was replaced with the ending of another film entirely. Rumor has it that Joe Dante was not allowed to finish his film and the studio forced its release "as is." This is really unfortunately, because Explorers could have been a great, classic film.

In all fairness, it isn't so much that the ending is bad. In fact, it is a fairly biting, but comical dig at human beings and our insane culture. As with all good satire, the jokes are punctuated by truth that will resonate with the adults, but everything is lighthearted enough to entertain the kids. The problem is that these scenes really don't fit the mood and tone set by the rest of the film. When the boys finally learn the true nature of the aliens, you can almost sense that they are as let down as the audience.

Explorers is still very entertaining and the early scenes are brilliant, but when, toward the end, one of the boys wonders, "is that all there is?" I found myself asking the same question.