After arriving back at home by helicopter, Chuck heads over a little late to Ellie and Awesome's to help them set up their television. After flashing on a news cast about Costa Grava's prime minister, Chuck gets called in on a mission, while Devon gets called to the ER. It turns out Devon was actually called in to help the dictator and ends up saving his life. While the public hears it was a heart condition, Beckmen and Operation Bartowski suspect otherwise. Chuck asks his brother-in-law, who's super interested in helping with spy stuff, and finds out it was from poison.
After telling Beckmen, the team gets assigned to protect the dictator, who doesn't realize people are trying to kill him. They must find a way to sneak into the gala undetected and save him from further assasination attempts. The dictator shows up to Devon's and invites him, Ellie and Chuck to the gala as guest. Chuck brings Sarah as his date and at the gala, Casey thinks he figured out who the assassin in. Chuck dances with Sarah over to the guy, knocks him out, only to discover the guy was merely a political activist. They get thrown out of the party and Casey is forced to enter. Unfortunately, Casey is the Angel De La Muerte of the title and is a wanted man in Costa Grava.
Casey sneaks in with a fake mustache and when he pulls the gun to go after the real assassin, Devon spots the gun and tackles him, getting Casey taken into custody. While interrogating Casey, the dictator gets poisoned and drops down dead. While the assassin is about to kill Casey, Devon is invited to the consulate to try and save the dictator. He sneaks Chuck and Sarah in as his assistants.
As Devon is trying to save the dictator, Sarah whoops the guards butt and she and Chuck go to save Casey. Casey, meanwhile, beats up the assassin while tied to a chair cause he's just that bad ass. However, on his way out, Casey gets shot and the guards force Chuck to save him to prove he's actually a doctor. In the end, the dictator needs Casey's blood for a transfusion to save him. The dictator sends a nice letter calling Casey the angel of life instead.
We also learn that The Ring mentioned in the pilot is responsible for the assassin and was trying to make sure Costa Grava did not become a democratic state. Interesting. Oh and more interestingly the episode ends with the assassin coming after Devon. Sarah reports the horrible news to Chuck.