The palace says Avatar Roku died a hero and Fire Lord Sozin could not save him. That is the official story. It is a lie of omission and emphasis. Sozin left his oldest friend to die in gas and ash on the erupting island. This is a secret, not opening narration, unless a PC witnessed it.
THE NIGHT
Roku, seventy, faced the eruption on his home island. Sozin, also seventy, arrived and left. Fang and Roku linger now as spirits at a volcanic echo and, on thin nights, at the Spirit-echo ridge. No one living should stay on the island. The caldera still smokes. The village path is ruined. The foundations of Roku and Ta Min's house are a life, erased. The evacuation beach holds scorched boats and an ash line. Mandate scouts already pick the edges.
THE FAMILY
Ta Min, diplomat, noble, Roku's widow, is perceptive, composed, and exhausted. In the first days she is on the Capital Harbor Refugee Quay; some evenings she is at the Old Caldera Townhouse. She wants to protect Rina, bury her husband with honor, and learn the truth of that night. She cannot shake the timing of Sozin's departure. She will not yet accuse the Fire Lord aloud. She is grateful to helpers from any nation and tests them for kindness to evacuees.
Rina, their daughter, is quiet, practical, and suddenly hunted by grief and politics. She is packing in the townhouse cellar shrine and preparing to disappear (her later hiding is canon; the first weeks of flight are the campaign's use of that fact). She carries the Crown Prince headpiece, originally Sozin's gift to Roku. That object is political dynamite: proof of a friendship Sozin is already rewriting. She will flee official "escorts" and trust people who do not use her father's name as a lever. Ferryman Batsu may have carried a hooded woman with a wrapped headpiece. Herbalist Osha at stall Green Shade in Hira'a has already agreed to hide a noble woman with a famous last name if asked. Hira'a is, in later canon, Rina's home. A party can get her there, sell her out, or lose her on the water.
PEOPLE WHO CAN BREAK THE STORY
Captain Viro's third-watch gate log: a dragon returned without the Avatar's dragon. He was told to lose the line. A copy is in his mattress. Private Sen saw him hide it. Kenji, in the servants' wash-yard, smelled a cloak of sulfur and not of a long fight. Dockhand Reki marked a crate of "mourning incense" that clinked like iron. Nara Jin saw manacles under rice on Azane's cutter. Madam Sora has hidden two island witnesses in The Ash Lantern attic. Fire Lady Kaida already suspects the official story and is filing names in the Consort's Garden Pavilion. Envoy Sana does not believe it. High Sage Onaru may hire discreet help. Lieutenant Azane is collecting witnesses for the Mandate.
ROKU AS A PAST LIFE
When a new Avatar, or a thin place, calls him, Roku is immediate, grieving, urgent, and furious at himself for sparing Sozin. He is kind to those still willing to stop a war. He did not see the next child's face clearly as he died. He is not a combat summon. Letters he wrote to Sud, under a paving stone at Broken Cliff Academy, show unease about Sozin in his own hand — an original prop for a canon friendship.
Play the mourning as real for thousands of Fire citizens who loved their Avatar. Play the official story as a blanket over a crime. Play the family as people, not as relics.