恶第四季

1. Boko Haram & Unnatural Selection: The Nigerian government is determined to drive militants from a terrorist group out of the country ; A new gene-editing method allow scientists to change the genetic traits of plants and animals.　　2. Escape to Europe; Cycle of Terror: Following the refugee trail from the Syrian border to Europe; The global reaction to the terrorist attack in Paris impacts the fight against terrorism.　　3. Right to Die: Exploring the moral, political and personal questions raised by euthanasia.　　4. Beating Blindness & White Collar Weed: Doctors and researchers make incredible strides in the fight against blindness; Struggling small-scale marijuana farmers face corporate takeovers as the end of the pot-prohibition nears　　5. Meathooked & End of Water: Examining the environmental harm of industrial meat operations; Assessing the depths of the world's water crisis.　　6. Return to Yemen & Church and States: Examining the conflict in Yemen; Exploring the ongoing battle for L