在上一次试图击败海王（杰森·莫玛 Jason Momoa 饰）未果后，黑蝠鲼（叶海亚·阿卜杜勒-迈丁 Yahya Abdul-Mateen II 饰）依然不甘放弃为父报仇，誓要消灭海王。这一次，他找到了传说中的黑暗三叉戟，释放出古老的邪恶力量，比以往更来势汹汹。为了与之抗衡，海王向被囚禁狱中的弟弟奥姆（也是前亚特兰蒂斯国王，帕特里克·威尔森 Patrick Wilson 饰）求助，组成了出乎意料的联盟。他俩必须抛弃前仇旧怨，携手并肩作战，才能从即将到来的灾难中保卫王国，拯救家人，拯救世界。
洛杉矶的飞机制造厂里，突然发生了一场火灾，工人伯金（Robert Cummings 饰）和朋友简奋勇救火，但简不幸葬身火海，事后调查发现伯金递给简的灭火器中装满了电油，于是警方将伯金定为重大嫌疑人，展开搜捕。获悉这一情况的伯金回忆后发现，灭火器实际出自一名叫做弗莱的工人之手，但警方并未给伯金说明的机会，危急时刻，伯金奋力逃出，追寻弗莱的去向为自己洗脱罪名。在弗莱工作过的农场，伯金发现农场主杜宾居然也跟此事有牵连，于是匆忙逃跑。亡命路途上，铂金结识了广告模特佩蒂（Priscilla Lane 饰），铂金用诚挚打消了后者对自己的怀疑，与她结伴同行。在弗莱可能藏身的荒僻小镇，伯金乔装成杜宾的手下，打入了这个神秘的破坏组织内部……
Petty Officer Michael Davis (Jeremy Davis) is the newbie to SEAL Team VI, but after his first mission the young soldier is weathered beyond hid years. His first assignment as for the elite black ops squad is as Communications Officer for the micro ground assault team that enabled surgical aerial assaults of strategic targets in Iraq, priming allied forces for the what is now known as Operation Desert Storm. The honor of being part of the special forces unit is enriched by the fact that he is invited into the unit lead by the best, Master Chief Devon Mackefy (Ken Gamble). The team, having just returned from one mission, is called into duty once again, because “Mac is the best”. Feeling the pull of the call, and given no option by the powers that be, our heroes go into the thick of it with the usual disadvantages - tired, short by one man and in need of gearing up in the weapons department; all with their invisibility being paramount. The team is rounded out by Petty Officer Williams (Kristoffer Garrison), Petty Officer Sanchez (Neta De Paula) and Chief Petty Officer Roberts (Zach McGowan). The team’s only contact ii Iraqi is Jamal (Amol Shah), a Kurd who has lost his family to the war and now helps the U.S. in these isolated covert operations. Their sole mission mark aerial targets, avoid capture and stay alive for four days. But the enemy is in every direction. Tensions are high since Davis is untested in the field and Mac is distracted by a recent personal loss. All these complications threaten the success of the mission, as well as the team’s survival.
