Ringworld Engineers

The deposed leader of an alien species kidnaps members of the old Ringworld scouting expedition in an attempt to find incredible machines which will help him climb back to glory on his homeworld. Unfortunately, the Ringworld is in danger from gravitational perturbations.

Motifs

• Bussard Ramjet

  The Ringworld ships use Bussard ramjets. They do not need to accelerate from a stop because the Ringworld is spinning at many kilometers per second, and acceleration/decceleration is handled by a series of magnetic mass drivers along the rim.

• Forerunner Race

  Humanity are revealed to be immature Pak, a species which needs "Tree of Life" to advance to its final stage, Protector.

• Magnetic Monopoles

  Magnetic monopoles are used for Bussard Ramjets by the Ringworld ships.

• Modified Humans

  Pak turn out to be the next stage in the human lifecyle, which can only happen if humans consume a substance called "tree of life", which warps them into the Pak Protectors previously described by spacers.

• STP Superconductor

  It is revealed that the Pierson's Puppeteers (an alien race of the series) released a fungus that eats and destroys the type of superconductor used by the Ringworld civilization to eliminate what they viewed as a powerful threat. Additionally, the ships have a supply of superconductor wire and cloth. Superconductor wire is used to instantly transfer heat from a weapon into a very large body of water, which then boils.

• Stellaser

  The purple hue that preceded the destruction the engines of the ship Lying Bastard is revealed to be a stellaser directed by the shadow squares structure that provides nighttime and energy to the Ringworld.