Maybe you can devise something like Romeo and Juliet meets The Davinci Code.
Torn apart by parental forces, separated by thousands of miles, their love is stronger and more meaningful than any simple text message.
The girl in her room, books stacked everywhere pages through an almanac, drops it and rushes over to a constellation chart, figures something out, quickly does a math equation, unfolds a map, follows a route with her finger and arrives at a town name etc. decoding from the ordinary a message of extraordinary love.
(In the end when the guy decides for whatever reason to call it quits, this girl is there like a crazy person rerunning and double, triple, quadruple rechecking the code, looking for something she missed, heart broke by the poems and staues and titles, and places and art works of the world, and the consellations beyond it.)
Maybe she even takes her own life, then we see she had a simple text or something waiting that tried to warn her of a typo in the code that gave it a whole other meaning never intended.
-Thanks-