巴克是一只骨骼壮硕身材强壮的狗，本来在大法官家里过着养尊处优的生活的它，被园丁偷走，卖到了严寒的阿拉斯加，成为了雪橇犬。巴克坎坷的命运并没有就此终结，之后，它又辗转经历了好几个主人，他们残暴而又冷酷的对待巴克。不仅如此，巴克在狗群中也为了保住自己的地位而经历了巨大的挑战 。 这一次，约翰（哈里森•福特Harrison Ford 饰）成为了巴克的新主人，幸运的是，约翰是一个善良的男人，他不仅非常温柔的对待巴克，还治好了它伤痕累累的身体。随着时间的推移，一人一狗之间产生了坚实的友谊。然而，在一场意外中，约翰被印第安人杀死了，愤怒的巴克失去了理智，它要为自己的主人报仇。

在上一季结尾，原分子病毒已经接管了爱神星并威胁到整个太阳系的安全。此刻，一个更大的控制原分子病毒的阴谋被进一步揭开。与此同时，联合国副秘书长Avasarala和火星军人Bobbie Draper正试图说出真相，阻止一场地球和火星之间的战争。而第谷空间站首领Johnson欲借此机会与地球和火星平起平坐。但是...神秘的生物已经脱离了控制...

本季将揭开全新篇章，“如今是改变和挑战、希望和恐惧、知识和无知并存的时代。”罗西南特的船员们接到任务：探索星环之门外的新世界。

本剧改编自詹姆斯·S·A·科里的科幻小说，讲述200年后一个被殖民的星系中，两个陌生人在不知不觉中卷入了一场巨大的阴谋。

Sheila Hood is an ex-cop whose marriage is on the rocks. Rather than confronting her husband about an affair, she hides surveillance cameras in her home and watches his transgressions, becoming a voyeur of her own life. Her husband, Tom Kale, is an ornithologist who begins an affair with an ex-girlfriend, Merle James, whose beauty and fragility echoes that of the birds he studies. Ray Starling, the charismatic owner of a boutique hotel, is Merle’s lover, and has dealings with her father, Mr James, a powerful oil baron who operates in the shadows but whose influence touches the whole city. Merle’s younger sister, Hazel, is also drawn to Tom, but trapped in Starling’s web of power. Calvin is an cop whose loyalty to his ex partner, Hood, is tested when mounting evidence from her own surveillance tapes connects her and Tom to Starling’s murder, and perhaps even Merle’s mysterious death.