The instant the download is finished, his phone emits a bright light, and transforms into a little girl the size of his palm.
"My name is Rin. What's yours?"
"The fact that you were able to download me must mean that you don't have a girlfriend... Am I right?"
"It'll be a bit of a problem for me if you don't become happy by Christmas. To put it simply..."
...If Hiro does not get a girlfriend by Christmas, Rin -- and Hiro's phone -- will vanish, and Rin will be unable to return to her world.