When the triplicator malfunctioned and created two new Red Dwarfs, the Dwarfers had to find whichever was the superior vessel, so that they could use its triplicator to reverse the process. They landed on the High Red Dwarf and Lister and The Cat went ahead.
They first encountered the High Lister and Cat in the corridor. Their higher selves knew immediately who they were and welcomed them aboard ship. They asked their original counterparts to join them in the sleeping quarters, which they had renamed the meditation chamber.
The Highs spent their time trying to unlock their minds and reach their full potential. They enjoyed music, dance, poetry and philosophy, making them extremely cultured and peaceful compared to the originals. They also had access to greater knowledge, which Kryten attributed to being able to remember everything that the originals had ever experienced. Rimmer was dismissive of the Highs, declaring them to be "Hippies", although Kryten pointed out that Rimmer thought Jesus was a hippy (Rimmer thinking so because Jesus had long hair and no proper job).
The High Lister was a soft-spoken and peaceful man, who played the harp during the entertainment provided for the originals. He carried pulses and curd in his pouch for the refreshment of others.
The High Cat disgusted his counterpart by wearing a robe and sandals. He told The Cat that he found clothes a distraction from the pursuit of spiritual and intellectual fulfillment. The Cat replied that his views were the exact opposite. He portrayed the role of "Truth" in an interpretive dance for the originals.
High Rimmer was an extremely calm and measured individual who explained their philosophy to the originals. He danced the role of "Agony" in the entertainment.
The High Kryten played the triangle during the dance and was as welcoming and trusting as his original. He offered to prepare refreshment for their visitors.
The High Holly interrupted the entertainment, much to The Cat's delight, to tell her crewmates that the Low ship was requesting assistance. She wore a hood like the other Highs and appeared on a screen that moved her image around randomly.
The Highs accompanied the originals to the Low Red Dwarf, but did not share their apprehension. High Kryten openly announced his peaceful intent to the Lows, who promptly shot him several times. He insisted that it must have been a weapon malfunction and that he still loved the man who shot him. He was equally pleased to see the Lows' next gift, "A sparkling welcome orb", which was a grenade that killed him and the High Cat.
Lister's body was then taken over by the Lows using a spinal implant, which allowed them to use him as a remote controlled killer. He found the High Lister and Rimmer, who despite wearing protective herbs, were unable to defend themselves. He was forced to stab High Lister to death and crush High Rimmer's lightbee. Both met their deaths with calm and pleasant expressions, to the point that High Lister apologized for staining Lister's knife with his blood (RD: Demons & Angels).