When Lou gets killed, Nick and Jacob fire up the hot tub time machine to get back to the past, but they inadvertently land in the future with Adam Jr. Now they have to alter the future in order to save the past, which is really the present.
Hot Tub Time Machine 2
When Lou's shot in the groin, Nick and Jacob drag him in the Hot Tub Time Machine to go back in time and save Lou. The three end up 10 years in the future, where they need to go to find the shooter.
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