交换：你兄弟

活力少女梦想着一场完美的成人礼，于是与孤独的新来者达成一项协议，但意外的心动和真相也许会让计划彻底泡汤。

一位孤立的私家侦探被一位朋友说服，从躲藏处出来帮助找到她失踪的妹妹，让那些想让他的家人死去的人能够找到他。

　　In the year 2961, the time is after humanity and nature has recovered the land. A hunter named Cygnus is called to rise above his duty. He provides for Last Arc, a once nomadic band of survivors in need of food and water that is now growing scarce. The answer must be found before a group of outlandish Heretics descend upon them. Cygnus must voyage across the treacherous landscape to defend his people. Sent by Nova, the matriarch of the band, she acts based on her vision for Cygnus to find a seed of hope. The future of Last Arc is for him to discover, Cygnus ventures into a hostile landscape in search of an answer for his people. On this journey of encountering many traps and dangers, Cygnus discovers what has been hunting him is his identity.

　　著名电台女主播萧潇雅（辛芷蕾 饰）在结婚前七天，因亲眼目睹名作家未婚夫李明轩与前女友许嘉雯（何佩瑜 饰）偷情，萧萧雅忍受不了背叛出轨的伤痛而自杀，幸被抢救复生，男友李明轩却坠楼身亡……是自杀还是他杀还没有揭晓真相，李明轩的前女友许嘉雯却又死于非命，李明轩的弟弟李明炎（张 哲瀚 饰）一直对哥哥的死觉得离奇，经调查发现偷情背叛事件出自许嘉雯和薛威（于毅 饰）策划的，在真相还没有大白前，薛威也相离奇死亡……谁是幕后真凶？是阴阳两隔的恋人的疯狂复仇？是横刀夺爱者的杀人灭口？还是宿命在爱情开始的一刻早已注定？