In the third novel of the Expanse series, the bizarre activities of the protomolecule on Venus come to fruition: from within the clouds of the planet a ring was launched toward Uranus, assembling itself upon arrival. Nothing has emerged from the Ring. There have been no signs of activity or life. Science ships from Earth and Mars hover near it, doing nothing but observing.
Neo, a young man with no ambition other than impressing his friends, puts together a ship which will slingshot him right through the Ring. Just as he nears the ring he’s hailed by a Martian ship who says they’ll fire on him if he doesn’t stop. Too close and too sure of himself, he sails through the Ring at high speed and is immediately crushed within his little ship.
Panic arises within the fleets. The little ship went in but didn’t come out the other side. There was some kind of reaction from the ring, they just don’t know what it means.
The biggest effect is on Holden and his crew. Just as they’re happily celebrating their successes and a bright future aboard the Rocinante, bad things begin to happen. Mars orders the Rocinante locked down at Ceres Station. They want the ship back. A client pulls out of their contract suddenly.
Miller appears to Holden when no one else is around. The fact that Miller is dead is annoying enough. The situation isn’t helped by the fact that Holden didn’t like him during the short time he knew him in life. Something about the disturbance at the Ring has Miller appearing more frequently and urgently, trying to get Holden to go to the Ring. Miller is cryptic and disjointed, he uses stories from his detective days to represent what he’s trying to convey. Holden understands nothing.
A documentary crew wants to hire the Rocinante to fly to the Ring, suddenly the place everyone seems to be headed. They also want one on one interviews with the crew that survived Eros Station. Faced with the possible loss of the Rocinante, the crew agrees and the long journey out begins.
A crew sets out from the Outer Planet Alliance. The Behemoth is a mix of Belters with a very few Earthers mixed in. It is seen as important that a ship representing the Outer Planets Alliance be commanded by Belters. Tensions are high.
On the United Nations Navy vessel Thomas Prince, Clarissa Mao, the technologically augmented daughter of Jules-Pierre Mao waits for Holden to near the Ring. She has been transformed into a highly efficient killing machine and will stop at nothing to bring him down, ruin his name, and end his life.
Representing Earth, a carefully selected group travels towards the Ring as witnesses and consultants. They’re represented by Anna, a pastor who hopes to help citizens of the solar system see how the presence of the Ring and what might lay beyond fits with what is known of God.
As all the ships converge on the Ring, a ship explodes, followed by an announcement that comes directly from the Rocinante and James Holden that he is responsible and claiming the Ring for OPA. In the chaos that follows, the Rocinante sends out a message that their signal has been hijacked and they did not set the bomb nor are they claiming the Ring.
In desperation, the Rocinante goes through the Ring. In short order, small tactical Martian Marine ships give chase, then all of the ships which journeyed to the Ring enter. The Ring has defenses that include keeping ships and probes and objects moving at certain slow rates of speed. It also reacts to violence in surprising ways. With each ship now full of panicked and sometimes mutinous individuals, there seems to be little hope any will make it out alive.