梅勒尼和艾丽是一对13岁的双胞胎,她们心地善良,聪明可爱,但性情不羁,对未来有着自己的打算和想法。在学校里两人功课学得很好,但是她们更渴望可以学到更多书本上没有的知识,比如如何与人相处。。In a near future, crimes and accidents can be prevented by making just one phone call to the past. However, the peace of this utopian world will be disrupted by a methodical killer who seems to have discovered the only flaw in this system.。