the 2 main characters are yuki and yuno. the plot is about diaries (usually in the form of hand phones) which can tell the future with each having its own special functions (e.g. yuki can predict what happens around him but not him while yuno can predict what situation yuki is in every 10 minutes).
A great manga to read, yuno is the pyscho girl with the hidden past. yuki is the naive and weak main character but sometimes shows his hidden strength. all the characters are unique and the story has many people back stabbing each other and using tricks. great story, not bad art and all around interesting series.
Read it to find out for yourself!!