The Harmony and Redemption was a space cruise ship that catered exclusively to wealthy mass murderers, with suites reserved for planet-burners. Even its staff was required to have a history of indiscriminate killing. Tickets cost a minimum of one billion credits.
During a tour of seven galaxies, the Harmony and Redemption ran into a meteor storm near Gamma Eridani and crashed into Darillium. Four centuries later, River Song dug up the wreckage, guided by History's Finest Exploding Restaurants.
With knowledge of the exact time of the meteor storm and the damage caused, River arranged for her sale of the Halassi Androvar to take place on the Harmony and Redemption just before the storm struck as insurance. After obtaining the Androvar on Mendorax Dellora, she arrived on the starship in the TARDIS with the Twelfth Doctor and Hydroflax, but would end up using the storm as a distraction and an escape when the deal turned sour. After fleeing Scratch, the ship's staff, and Hydroflax's body, River and the Doctor attempted to stabilise the ship but ultimately failed. As the two fled into the TARDIS, the ship crashed on Darillium in front of the Singing Towers and was destroyed.
The next morning, a workman named Alphonse searched the wreckage for survivors, but only found the Doctor and the TARDIS. The Doctor stated there likely weren't any other survivors and that the deaths of everyone on the ship wasn't regrettable. The workman, using the reward money from the return of the diamond, would later build a restaurant upon the spot the ship crashed. Hydroflax's robot body was recovered from the wreckage and now controlled by Nardole and Ramone, worked at the restaurant that was built. (TV: The Husbands of River Song)