Ultramarines: A Warhammer 40,000 Movie

A dawn patrol of Imperial Fists on the desert world Mithron meets a shadowy foe. Nidon is ordered to protect the Codex as a blazing fireball swallows the squad, ending the moment with devastating loss. The event seeds the mission's sense of peril and the cost of vigilance.

Aboard a Strike Cruiser, Captain Severus of Ultramarines tests the newly formed Ultima Squad in a tense sparring match against Proteus. Proteus comes out on top, disarming Severus, yet the Captain refuses to yield, establishing mutual respect. The encounter also underscores the presence of the sacred Thunder Hammer.

In the reclusium, the Relic Thunder Hammer gleams as a rite of passage. Severus leads new initiates in a solemn oath around the hammer, binding Ultima Squad to a perilous duty. The ceremony marks their readiness for what lies ahead.

Ultima Squad departs the Strike Cruiser toward Mithron, with Pythol and the ten-man team accompanying Severus. A distress call guides their approach, though its origins remain uncertain. The squad steels itself for what awaits on Mithron’s surface.

From orbit they descend into Mithron’s harsh desert toward the Imperial shrine guarded by a full company of Imperial Fists. The Marines push forward despite a creeping sense of danger, drawn toward a focal point of the invasion. The environment is unforgiving and tense.

Proteus senses a watching threat that never fully materializes as they reach the shrine. The site lies ruined, its garrison fallen and desecrated by Chaos forces. The Ultramarines press on in search of survivors and answers.

Despite Pythol’s counsel to withdraw, Severus pushes deeper into Mithron to uncover survivors and the truth behind the invasion. His stubborn resolve sets the stage for further confrontation with Chaos. The squad moves deeper into the ruin.

The Ultramarines are ambushed by Black Legion forces. Three Ultramarines fall—Crastor, Lycos, and Boreas—in a brutal, decisive assault. The squad fights onward through the shrine’s broken corridors toward the reliquary.

A Daemon Prince materializes in the darkness, killing Brother Maxillius and grappling Severus, sending both plunging into a ravine. The encounter marks a brutal turn, as Chaos asserts its hold over Mithron’s depths.

With Severus gone and Crastor dead, Proteus assumes command and leads the unit toward the reliquary in a bid to safeguard the Libr Mithrus. The mission shifts from discovery to defense against a Chaos onslaught.

The squad reaches the reliquary and discovers Chaplain Carnak and Brother Nidon guarding the Liber Mithrus. The two veterans reveal they have safeguarded the book since the chapter’s founding, and Ultima Squad agrees to escort it to safety while grappling with possible Chaos taint.

A massive Chaos counterattack erupts as casualties mount: Remulus falls and Junor sacrifices himself to hold the line. In a shocking turn, Severus returns to aid their escape, revealing a deeper treachery at work.

Back aboard the Strike Cruiser, Proteus confronts Severus’s hidden treachery and learns that the Liber Mithrus is more than a simple codex. Hypax returns bearing the Ultramarines’ standard, and Carnak is killed in the ensuing confrontation, confirming the taint remains even after Carnak’s death.

Severus reveals his body is possessed by a Daemon; the plan is to transfer the daemon into Proteus to strike Macragge from within. Hypax acts to foil the plan, driving the daemon toward the ship’s armory where it can be contained.

Pythol sacrifices himself to save Proteus from possession, buying him time to seize the Thunder Hammer and strike down Severus, banishing the Daemon back into the Warp. In the aftermath, Proteus is promoted and a new vigil begins as the hammer ceremony continues with a fresh generation.