The party receive their briefing from Cpt. Abiding Storm aboard Her Glorious Command where she explains that a shuttle carrying an Altarian Ambassador due to take up governership on Siruta has gone missing. They're tasked with retrieving them, or finding out what happened.
The party make their way down to Azuria on Siruta, where the Ambassador was due to arrive, and after dealing with some enemy crabs that were roaming the streets during a strange Azurian Observance decreed by the spiritual mystics, determine that the shuttle - the Best Of Intentions - must have been downed outside of Ship Hearted space and so they'll need transport that is resistant to the Decay. They find and work with Captain Violet Afterburn who takes them aboard her ship - the Justification - which is an old fashioned wooden vessel with a set of large afterburners attached - something that Moon and Relaxation both remark on as out of place.
As they're due to board the ship, they meet the quartermaster of the ship - Doubled Chainshot - who is suddenly set upon by dockyard goons and appears to be fatally stabbed by an Elegy Spectre (Spectre Orion). Luckily for them they have a lucky charm which prevents this Severe Injury from being fatal, and the party proceed to interrogate Orion. Orion explains that Chainshot was selected for pruning by the Elegy, and Chainshot speculates this is due to a false belief that Chainshot assassinated the Ambassador. Chainshot reveals themself to be an Altarian Dynast - 332 - but claims innocence about the Ambassador's attack. The party persuade Orion to wait for them to return to determine whether or nor Chainshot did in fact do the crime they're said to have committed.
The Justification leaves port, and after a battle with some Scourgelings - small forms of a much larger Scourge somewhere out there - they are invited to dinner where they discuss the variety of Scourges, Doubled Chainshot's concerns about the Ambassador (Pentagonal Pectoral, 313) and their competence, the Orion Gate failure, and during which Violet Afterburn confides in Tiny Ember that she is also an Altarian Dynast, the runaway black sheep of the family, order of 37.
They finish dinner, and Ember has the idea to tinker with her communicator to create a scanner to triangulate the crash site of the Best Of Intentions. She does so and is able to navigate the ship toward a wreck site. With some clever distraction, the Decaying trackers infesting the site are avoided and they retrieve the Solar Shielded Flight Recorder from the wreckage and make their way to an island to play back the recording.
Relaxation is able to get the Recorder to play back and understands that the Ambassador has been able to make their way to safety in an underwater cave system. Relaxation repurposes a rudimentary O2 supply on the rowboat they're using to construct some SCUBA packs, and the party dive through some caves to find the Ambassador on their own, surrounded by the dead crew who tried to help them. They explain it was a Scourge that attacked the ship and, grateful for the rescue, don an O2 breather that Ember tinkers with to make their way back to the Justification.
The ship, under siege from Decay, welcomes them back on board to fight off waves of Decaying creatures, but during the fight Doubled Chainshot makes an attempt on the Ambassador's life. There's a tense Altarian stand-off with Chainshot and Pectoral, during which an indignant Violet Afterburn reveals her station as the rumoured 37 in system reported by Moon. She insists she doesn't want to use her station, but Pectoral requires convincing to take the position that should obviously go to Afterburn in their mind. After some tense negotiation, and a failed backstab from Chainshot against his captain, Pectoral agrees to take the position but the party note that Afterburn would be better positioned with her knowledge to take the position.
Leaving the wreckage, the silhouette of a full-grown Scourge appears and an enormous monster breaches the surface of the water. Ember punches the Afterburners and the ship rockets back toward safety as the party fight off wave after wave of Scourgeling creatures, ending up infected by some fo them, but able to make it safely back with the Ambassador as the Craruan Defenders arrive to engage the Scourge with giant robots.