Dark Age
Picking up immediately, on the hottest world in the system. The saga's longest, bleakest and most relentless volume.
Mercury falls. Orion goes mad and is executed. Lysander raises Heliopolis. Mustang flees Luna. Volsung Fá takes the Volk, and Ephraim dies. Cassius pulls Darrow from the ruin, and the Republic believes the Reaper to be dead.
Plot in detail
Darrow: he has Orion raise hypercanes on Mercury, then executes her when she goes rogue. He holds Heliopolis until Lysander's forces beat his army, and Cassius carries him out of his last stand.
Virginia: she is framed for a poisoning, and Publius's riot kills allies including Daxo. She escapes Luna, leaving Sevro behind, and takes emergency powers on Mars.
Lysander: he kills Alexandar, leads a rising in Heliopolis, and agrees to marry Atalantia. Then Kalindora tells him who ordered his parents' deaths, and he secretly allies with Apollonius.
Lyria and Ephraim: Lyria, abducted by Figment, infiltrates the Red Hand and calls in the Martian civilians who help defeat it; Harmony is killed. Ephraim exposes Xenophon and is killed by Volsung Fá.