One day Hibiki Kuze and Daichi Shijima are sent strange videos via an app on their mobile phones; it appears to show their deaths. Moments later they are caught up in a train crash but survive when a 'Demon Summoning App' installs itself onto their phones. Another survivor is school friend Io Nitta. They escape as demons eat the victims of the crash. More demonic creatures appear but they fight them off using the App. Afterwards they are taken into custody and learn the world is being attacked by beings known as 'Septentriones'; if they aren't defeated in one week humanity will cease to exist. They, and fellow summoners, are recruited into an organisation known as JPs to lead the defence of Japan. JPs is led by Yamato Hotsuin; who has sinister plans of his own. Before each battle they continue to receive videos predicting friend's deaths; will these enable them to avoid the predicted fates or are they doomed? If you like anime with plenty of action in every episode this may be for you; it nicely combines technological elements with the fantasy of summoning beasts to fight off attacks. It isn't just as case of heroic humans battling evil invaders; it is clear from early on that Yamato intends to use events to create a world that will only support those people he deems worthy. I must admit I found certain elements a bit confusing early on but things later came together fairly well. As the story progresses we learn more about the Septentriones and it becomes clear that not everybody who appears to be an important character will survive. The animation is pretty good with frequent dynamic action scenes. Overall I'd say this is worth watching if you are a fan of the genre. These comments are based on watching the series in Japanese with English subtitles.