Like much of Niven's work, the story is heavily influenced by the setting: a gas torus, a ring of air around a neutron star.

Twenty astronauts aboard an interstellar "ramship" colonized the Smoke Ring five hundred years before the story begins.

The tribe's leader, the chairman, decides to send a party of nine up the tree, ostensibly to hunt and re-cut tribal markings into the trunk.

When they approach the midpoint they notice that the tribal markings are different; upon reaching it, they are attacked by members of the Dalton-Quinn tribe who live at the other end of the tree.

The seven surviving members of the Quinn Tribe and one of the attackers jump clear of the shattered tree and are left adrift in the sky with only a few "jet pods" (high pressure seed cases that provide a temporary thrust when opened) as their only method of propulsion.

Before dying of thirst, they hook a passing "moby" (a flying whale-like creature) which takes them to a "jungle", which is a floating mass of plant life.

They cut loose, crash, and find themselves in the middle of a battle between the Carther States, who live in the jungle, and slave-runners from London Tree.

During the battle they steal London Tree's CARM (Cargo And Repair Module), a small spacecraft—a relic of the original settlers.

The CARM is still functional due to careful management and its robust design; its solar panels provide electricity to electrolyze water into hydrogen and oxygen, which it stores automatically and then burns for propulsion as needed.

London Tree's "Navy", bow- and spear-armed warriors, use the CARM to conduct long-distance military actions and slave raids on a scale impossible for wingless humans in a zero-g environment.

Unknown to any of the inhabitants of the Smoke Ring, Discipline, the ship in which their ancestors arrived, remains in orbit, and its AI autopilot, Kendy, has been attempting to watch their progress.