Ctrl Alt Escape by Marta S. Pina and Jeremy M. Williams
It's only in Spanish.
Synopsis:
During the last few weeks before the holidays, Monica and Carlos, two 16-year-old teenagers, begin to receive strange messages through the computer from someone who claims to be from the distant future and needs their help.For eight days they will be forced to miss class, lie to their parents and even betray their friends, endangering their own lives to fulfil a mission as inexplicable as it is indispensable: the future of humanity is in danger and only they can save it.
Recommendation:
Science-fiction, mystery and adventure.
This book is about following two teenagers that are speaking with a person
of the future. If you like all of this stuff you must read it.