Anthem is a shared-world action RPG, where players can delve into a vast landscape teeming with amazing technology and forgotten treasures. This is a world where Freelancers are called upon to defeat savage beasts, ruthless marauders, and forces plotting to conquer humanity.

A famed Freelancer named Haluk rallies an army of Freelancers to enter the Heart of Rage and deactivate the Cenotaph. Among them is the player's unnamed character, a rookie undertaking their first mission. Accompanying them is Faye, Haluk's own wife and Cypher. Shortly into the mission, all the other Freelancers are killed, prompting Faye to call a retreat, with the player evacuating a wounded Haluk. The resounding failure causes people to lose faith in the Freelancers, whose ranks are now decimated.

Two years later, the player has settled in Fort Tarsis, a frontier city between The Heart of Rage and Antium, Bastion’s capital. Partnered with a young Cypher named Owen, they make a living completing modest Freelancer contracts for the locals. Owen aspires to be a Freelancer, despite his psychic abilities being a hindrance to piloting a Javelin.

An agent of Corvus named Tassyn hires the player to locate a spy who went missing while undercover with a smuggling gang called the Regulators. At a devastated Regulator hideout, they encounter a Dominion leader called The Monitor. The Monitor is a powerful Cypher, a skilled Javelin pilot, and participated in the assault on Freemark that created the Heart of Rage. The Monitor executes Tassyn's spy and takes a Shaper relic that they were hiding. Tassyn surmises that The Dominion is collecting relics for another attempt to reach the Cenotaph, and rehires the player to reach the Cenotaph first. She also notes that Haluk and Faye have spent the past two years developing a new plan to deactivate the Cenotaph, recruiting the pair to Tassyn's mission.

Faye and Haluk believe that the only Javelin able to survive the Heart of Rage is General Tarsis’s legendary Javelin of Dawn. Using clues found in the tombs of Tarsis’s Legionnaires, they locate Tarsis’s secret tomb. Within her tomb, the player's obtains Taris's signet, which acts as a key to the Fortress of Dawn- the site of Tarsis's last stand and the Javelin of Dawn's resting place. At the Temple of Dawn, the player is challenged by trials of skill and resolve. After reenacting Tarsis’s last stand, an apparition of General Tarsis declares the player to possess the qualities of a Legionnaire of Dawn and grants access to her Javelin. Before the player can take possession of the Javelin of Dawn, their own Javelin freezes up. Owen appears and takes credit for sabotaging their Javelin so he can take the Javelin of Dawn for himself. He plans to accept The Monitor's offer to spare Fort Tarsis in exchange for assisting him with the Javelin of Dawn, and accuses the player of keeping him from his dream to be a Freelancer. Before Owen leaves in the Javelin of Dawn, Faye scans its unique shielding module, the Shield of Dawn, hoping that it can be duplicated so the player can enter the Heart of Rage with their own Javelin.