这是波洛与法国警方的一次合作，其实确切的说是一场较量，结局自然是波洛大获全胜。
正在伦敦的波洛收到一封法国来信，一位署名雷诺的百万富翁称自己的生命正受到威胁。当波洛携好友黑廷斯火速赶到雷诺先生在法国的别墅时，这位百万富翁却已经遇害，尸体被抛在别墅后正在建造中的高尔夫球场的一个墓穴.......... 波罗在侦破过程中，发现插在尸体上的金丝把匕首不翼而飞，追查中找到两把一模一样的匕首。然而，波罗要找的却是第三把匕首……

In a time now lost in the mists of memory, the great King Arthur rules in the legendary citadel that is Camelot. His Knights of the Round Table perform acts of derring-do and spend their spare time jousting, much to the delight of the local citizens and especially to Princess Ilene, a guest at Camelot. Watching her from afar is a young, inexperienced squire called Valiant, and when the young Welsh princess is sent home to marry Prince Arn, Valiant contrives to accompany her masquerading as Sir Gawain. Meanwhile, the evil sorceress Morgan le Fey, sister to King Arthur, has convinced the tyrannical Sligon, ruler of the Viking kingdom of Thule, that he should steal Arthur's sword, the powerful and magical Excalibur, knowing that its loss could bring about Arthur's downfall. So into the fray comes Sligon's unstable and psychotic brother Thagnar, who manages to steal the sword. Pandemonium reigns. But Valiant is having problems of his own - kidnappers attempt to steal away the Princess, and after various skirmishes, including one with a mysterious character who lives in a cave and purloins treasure, women and other things of value, Valiant manages to return the Princess to her homeland - although he also manages to have a duel with the Princess' jealous fiancé, Prince Arn. All things converge as Valiant is finally informed of his heritage by the stranger from the cave... Boltar of Thule. He informs the lad that he is Prince Valiant, rightful heir to the kingdom of Thule, and with his help, Valiant returns to the land of his birth to rightfully claim what is his.

在大洋中央的一个军事哨所服役两年后——四名士兵正在等待新船员来接替他们。 当期待已久的船终于出现时，船上空荡荡的，没有浮雕。 当试图找出船和失踪船员的下落时，他们意识到他们已经失去了与家的所有联系。 贝恩斯、沙利文、卡西迪和亨德里克斯与世界其他地方隔绝，也没有人来接他们，他们必须在相互怀疑的情况下进行斗争，并找到一条回家的新路。 如果家还在。