During her first night on the job, a rookie EMT and her partner pick up a wounded superhero and are pulled into his mission to save Los Angeles from a sinister organization.
In Los Angeles, it is Lauren's first night as an EMT. And what a night it is. Wait, go back. Then go back again. And back again several more times. And the action finally returns to the beginning. Lauren has a drug problem and she wants to use but apparently ran out. But she calls her sponsor and they talk about her struggle.
Eddie is the driver and he is hard on the newbie. He seems like a jerk but does have a caring side. He listens to a real wacko on the radio who believes in crazy conspiracy theories.
Several ambulances are called to an explosion. On the way, Eddie and Lauren encounter a man lying in the road ranting like the man on the radio. Rather than go where they were told, they pick him up and prepare to take him to the hospital. But all forms of communication are lost, so they can't explain to anyone what they did. The man is a military veteran whose last name is Armstrong. And maybe this is the reason for the film's name: it's not certain he is human, and his arm has super powers.
Before they get to the hospital, Eddie and Lauren must deal with someone--or something--resembling Darth Vader. And he has serious weaponry. Now it's time to learn the truth: Armstrong was responsible for the explosion. it had to be done to prevent The Harbingers of the Fifth Sun from destroying the city. The Fifth Sun is related to an Aztec belief, and apparently the world needs to be destroyed. Armstrong is the one person who can keep that from happening. Or is he? Another soldier says Armstrong escaped from a facility and he's nothing more than a lunatic terrorist.
