In Death by Lightning, Netflix turns a chapter of American history into a thriller. Based on Candice Millard’s Destiny of the Republic, the four-part miniseries dramatizes the assassination of President James A. Garfield and the bizarre mind of his killer, Charles J. Guiteau.With Michael Shannon playing Garfield and Matthew Macfadyen as Guiteau, the finale of Death by Lightning leaves many of us stunned and questioning how history could have gone so horribly wrong.Let’s break down what really happened, what Netflix dramatized, and why the ending of Death by Lightning stays with us, shall we?Death by Lightning ending: What really happened to President James Garfield?The finale opens with brutality. President Garfield was just months into his term and hopeful about uniting a nation when he strolled into Washington’s Baltimore and Potomac Railroad Station. There’s no security, just his sons and Secretary of State James Blaine (Bradley Whitford). View this post on Instagram Instagram PostThen, two shots ring out. The bullets come from Guiteau, a deranged office-seeker who believes divine destiny demands his act. Though Garfield doesn’t die immediately, the real villain is 19th-century medicine itself. His doctors, led by Dr. Bliss (Željko Ivanek), refuse antiseptic methods and probe the wound with unwashed fingers and instruments.Garfield suffered months at the White House, attended by Dr. Purvis (Shaun Parkes), the first Black physician to treat a president with infection and sepsis. He dies on September 19, 1881; it’s also a failure of science and hubris.Death by Lightning ending: Why did Charles Guiteau kill him?On Death by Lightning, Matthew Macfadyen flips between pathetic and terrifying. He genuinely believes murder is his ticket to immortality.As the show reveals, Guiteau once supported Garfield and wrote speeches he believed made him indispensable to his campaign. When the administration denied him a consulship in Paris, Guiteau took vengeance. His mantra is absurd yet bone-chilling: "Arthur will be President! The Republic is saved!"Guiteau sees himself as a patriot, by the way. His trial scenes show his delusional self-defense and a posthumous plea to publish his book, The Truth. Ultimately, he’s sentenced to death by hanging. In his final moments, he recites an original poem (I Am Going to the Lordy) to a crowd.In the finale, Guiteau’s brain is dissected and preserved at the U.S. Army Medical Museum. History couldn’t look away from the madness, it seems.RELATED: Does Death by Lightning Take Inspiration from True Events?What happened to Lucretia Garfield and Chester Arthur?What comes after the assassination is perhaps the most devastating. Betty Gilpin plays Lucretia Garfield, and in a fictional (but unforgettable) scene, she confronts Guiteau in prison, as she tears apart his delusions and vows his "legacy" will rot with him. View this post on Instagram Instagram PostIn reality, Vice President Chester A. Arthur (Nick Offerman) does ascend to the presidency. Initially portrayed as an opportunist, Arthur has a moral reckoning. The closing title cards reveal that he enacts civil service reforms.The Garfields gather around the wooden table James built, his empty seat still there. The epilogue also tells us that Lucretia lived 37 more years.Death by Lightning is now streaming on Netflix.