The reason why Artoo is in every movie is because it likes collecting famous, exciting meatbags. Famous, exciting meatbags are always having cool adventures, and Artoo is an adventurous kind of droid. This has been going on since before the Phantom Menance, and Artoo has developed a talent for recognizing famous, exciting meatbags before they become famous and/or exciting. And these new human-type meatbags? Trooper-model, Pilot-model, and Jedi-model? It knows they're going to go far.

The trio find themselves stalked by this wily, old astomech who is hellbent on worming its way onto their team. However, BB-8 is furious that R2 is trying to steal its humans!