AND SO IT BEGINS... 
(Episode 1) 

Seven kids (Tai, Sora, Matt, T.K., Izzy, Mimi, and Joe) at summer camp witness some mysterious weather.  Seven objects fall to the earth from a light in the sky and levitate in front of the children.  The children take these objects are transported to another reality (they later discover these objects are called "digivices").  

The kids are befriended by a group of strange creatures who call themselves "Digimon," digital monsters.  It's the "In-training" form of the digimon that first greet the kids.

The seven companion Digimon prove to be more than good company when they transform into larger "rookie" digital monsters and fight as a team to defend the kids from a giant red beetle Digimon.

If you're curious about which digimon are partnered with the kids, check out the season 1 evolution chart