The twitter-short version:
Old, sleepy robot dreams of past glory. Wakes, decides to catch up with old friend.
The slightly longer blog version: (spoilers)
All those blogs complaining of plot holes and the like in The Force Awakens? They’re way off track. The explanation is so simple. The whole film, bar the last ten minutes, are just a dream that R2D2 has. He’s remembering a bunch of stuff that happened years ago, but as is the way with dreams, some of the details have got a little mixed up, and the dream characters are much better-looking than the reality (in my dreams, I’m always played by John Cusack from High Fidelity-era… stands to reason). Instead of John Cusack, R2 imagines he is BB-8 in this dream. He’s a few pounds lighter, some might say better-looking, definitely more agile…
Just be grateful the directors cut that scene with R2-She2…
So, R2 has a merry dream about the good old days, fighting the Evil Empire, blowing up Death Star things and the like. He then wakes up, and decides it’s time to have a little catch-up with his old friend Luke Skywalker, especially now that stinky Dagobah is out of the equation.
It all makes perfect sense!
The alternative is explained at some detail in the following link – http://www.outerplaces.com/science-fiction/item/10850-r2-d2-s-role-in-star-wars-the-force-awakens-explained , but involves a string of convenient plot devices, fortuitous timing, dull dull dull defragmentation of hard drives or somesuch, and Force-y Worce-y logic.
I know which my money is on.
But that’s ridiculous! I hear you cry, indignant fists bashing into your smartphones. No top rated entertainment show would be so crass as to use the “it’s all a dream” approach. Really?
Exhibit A – Dallas – Bobby Ewing, and a shower. Everyone knows this one. (So, Han fans, do not give up hope yet.)
Exhibit B – Neighbours – this fine Australian daytime soap (previous home to Kylie Minogue, Guy Pearce, and Russell Crowe, among others) actually based an episode around the daydreams of a dog… Bouncer’s Dream. (This is not a joke. See #10 on this list – http://www.bbc.co.uk/news/entertainment-arts-31914133 .)
Exhibit C – Lost – this must have all been a dream, right? It just doesn’t make sense otherwise…
So, you heard it here first. “The Force Awakens” is simply code for “R2 Awakens“.