Après avoir visité la Lune et Mars, les Chevaliers de l'Ether semblent tristement cloués au sol depuis l'échec de leur tentative visant à convaincre l'Empereur Napoléon III de secourir les Martiaux. Le jeune Séraphin a été jeté en prison, et la Princesse de Mars est détenue pour être exhibée lors de l'Exposition Interplanétaire qui doit s'ouvrir à Paris, le 25 avril 1875 en présence de leurs Majestés les Empereurs de France et d'Allemagne....

Planète Mars, 1873 : Séraphin et ses amis escortent la Princesse et son peuple à travers les hauts plateaux. La colonne de martiaux fuit l'invasion prussienne, et espère trouver refuge au-delà des terres interdites du pôle de Mars. Mais les phénomènes étranges se multiplient, et les aigles de guerre de Bismarck menacent... Poussés au bord du désespoir, leur salut viendra-t-il des reliques d'une antique civilisations martienne, ou d'une...

"An alt-history account of the founding of America, as a lost fleet of Roman soldiers arrives a thousand years before Columbus. In AD 323, a fleet of Roman ships is lost in a storm, and they find themselves on the shores of the New World, one thousand years before Columbus. Unable to return home, they establish a new colony, Roma Occidens, radically altering the timeline of America and subsequent world events as seen through the eyes of one family....

"Hank travels in search of Cain, who proceeds with the Incarnate research that Elaine left unfinished. Schaal, held captive by Cain, learns about her power and must choose whether to sacrifice herself for the future of the Incarnates. Meanwhile, Claude searches for his own way to protect the nation and its people as the Northern Union of Patria prepares for war. Each of their paths comes winding back together as the story heads for its grand finale..."--Back...

"When her sister seizes the throne, Queen Eleanor of Albion is banished to a tiny island off the coast of her kingdom, where the nuns of the convent spend their days peacefully praying, sewing, and gardening. But the island is also home to Margaret, a mysterious young orphan girl whose life is upturned when the cold, regal stranger arrives. As Margaret grows closer to Eleanor, she grapples with the revelation of the island's sinister true purpose...

Our two spatio-temporal agents are on a new mission, but this time the duo is split up. While Laureline flies solo from planet to planet, on the trail of arms dealers and forbidden technologies, Valerian is on 20th century Earth, teamed up with the eccentric Mr Albert. And he, too, is hunting down technologies incompatible with the era. What is the link between the two cases, separated as they are by centuries and light-years?

It's the fifth volume of the world's greatest secret science history, The Manhattan Projects. "The Cold War" reveals the dark days of the 'real' Cuban Missile Crisis, the assassination of an American President, and the end of the Manhattan Projects-Star City alliance.