the latest episode titled global extremism. let's watch a clip. >> 130 people were murdered, hundreds more wounded. some of the terrorists have come from the isis caliphate where the attack was planned. others were born in france and belgium. according to this man the work of prosecutors were needed. he showed me how they pieced together the evidence. >> careful investigative work. tell us what's going on and what to expect this season. >> that particular episode is about the true face of terror inside the isis caliphate and it is fascinating. these investigators have been on the ground talking to people freed and many of whom were slaves and many children and discovered something that we really missed in the whole conversation about terrorism. islamic terrorism. that is that the caliphates and isis is all about the next generation. it is about the children. it is about the messianic