朋友夫妇：交换

　　火、水、风、土、和空气，生命五种核心元素曾经注入在一本书--命运之书。黑暗笼罩了大地，需要借助笔和书的力量，但这本书却失踪了，人们以为它永远消失了，但数百年后却又再度出现……

　　In “Muzzle: City of Wolves,” Jake Rosser (Eckhart), haunted by PTSD from his days as a K-9 officer, endeavors to lead a peaceful life with his family and retired K-9 companion, Socks. But the tranquility quickly dissolves when a ruthless gang targets them in a brutal attack. Determined to protect his loved ones, Jake and his new K-9 partner Argos delve into a violent underbelly of crime where Jake confronts corrupt officials, uncovers a perilous drug trafficking ring and battles his own inner demons.

 本片改编自同名小说，讲述了主人公·梓失去了无可替代的挚友而止步不前，她不断给已故好友发送信息，由此开始，意想不到的邂逅接连发生，形成了一个巨大的圈子…