Pre-Ringworld
In an adventure related in Betrayer of Worlds, that he does not recall in his later life (e.g., in Ringworld), Louis is found by a Pierson's Puppeteer named Nessus while working in a hospital in a rebel camp on Wunderland and severely addicted to pain killers. Nessus is attempting to find members of Louis' family, but Louis reports them dead. Desperate and hoping Louis has similar talents, Nessus recruits Louis with the understanding that his memory would be altered before his return to Known Space, he would be saved from the Civil War on Wunderland, well compensated and cured of his addiction.
Louis' task is initially to prevent a war between the Puppeteers and Gw'oth. He eventually ends up preventing a genocide, observing the removal of the legitimate Puppeteer government, its ironic replacement with a puppet regime controlled by the Gw'oth, and finding himself with a very large Puppeteer bounty on his own head. Taking it for granted that he would eventually be discovered in Puppeteer regions of space, he agrees to let Nessus alter his memory and return him to Known Space.
He awakens on a very expensive FTL singleship near Known Space, physically younger than he recalled, unaddicted (the ship refuses to provide him with alcohol or pills), and without recollection of how he came to be in this situation while several months away from Sol and Wunderland. He attributes the memory loss to pill usage and resolves to sell his ship as soon as he arrives back in the Sol system.
Louis Wu later appears in the short story There Is A Tide, where he becomes the first human to make contact with the Trinoc species. (Chronologically, this story falls between Betrayer of Worlds and Ringworld.)
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