Of course, they think of novel ways to use their new found toy such as winning the lottery. I wish I'd thought of that. They also come up with some rules like don't change things in the past that can alter the present. But rules are made to be broken and obviously these kids didn't see the movie The Butterfly Effect. Hey, they got a time machine so things can be fixed. Not! Situations go from bad to worse to wish I had never opened the secret door where the plans were hidden.
You should be able to figure out the ending to this one unless you are totally new to time travel flicks. I'm not going to spoil it here. Sorry to say, I did figure it out.
Two things I liked about the movie is how the father kept the plans hidden. Trap door in the floor had electromagnets that kicked on when the basement lights were turned on. Of course, the unusual thunking sound of the magnets turning is what first tipped the kids off. Interestingly no one discovered this in the ten years that the father had disappeared. But maybe they don't go in the basement a lot.
The second is...hmmmm! I guess there is only one thing.
I give this a sad two star review. Here is trailer.