This is another installment in the camping series, in which Calvin's dad drags the rest of the family on a trip to an island. Thankfully, Calvin has brought along his Hypercube in which to store things.
Anyway, the group goes on a hike, where it eventually becomes obvious that they're lost. Calvin finds the tents fifteen minutes later, and he refuses to come out of his.
Dad bugs Mom to go on a hike, and she relents. Calvin, of course, is snoozing the day away. Unfortunately, a rock slide happens, trapping Mom and Dad in a cave!
At around three, Calvin and Hobbes awake, and soon discover their parents are missing. They use the MTM to find them and start hiking.
They come across a rock, which the MTM says is where they are. Calvin blasts it to pieces with the MTM, and they reunite with their parents, shortly returning home.