Iris Winnow bid farewell to her brother, Forest Winnow, as he left for a war ignited by the Underling god Dacre, promising to care for their mother and stay in school while they exchanged letters and his trench coat. Months later in Oath, Iris worked at the Gazette in cutthroat rivalry with Roman Kitt for a columnist post, chafing under editor Zeb Autry’s ban on war coverage and secretly writing raw letters to Forest on her grandmother’s rare Alouette typewriter. Those letters began vanishing beneath her wardrobe and returning answered by an anonymous correspondent, whose voice steadied her through poverty, newsroom setbacks, and the city’s denial of the growing conflict.

As reports of monsters and missing lore surfaced, Iris’s research hinted at deliberate erasure of knowledge about Dacre and the eithrals. At home, her letter exchange deepened with the unseen partner who urged her to lower her emotional armor, even as her mother, Aster Winnow, spiraled into alcoholism and was then killed by a tram, shattering Iris’s world. Grief-stricken, Iris resigned from the Gazette after Roman won the column, decided to seek the truth at the front, and joined the Inkridden Tribune under Helena Hammond, who recognized her typewriter as the Third Alouette. En route to Avalon Bluff, Iris befriended fellow correspondent Thea “Attie” Attwood, learned the town’s siren rules from Marisol Torres, confirmed her long-distance magical correspondence, and began writing letters home for wounded soldiers while pursuing the missing half of the Enva–Dacre myth.

Back in Oath, Roman confronted his father’s schemes and the hollow engagement to Elinor Little, hid Iris’s saved letters, and eventually followed Iris west as a Tribune correspondent. In Avalon Bluff, Iris and Roman’s guarded truce thawed through shared work, morning runs, and the revelation—first hinted in myth exchanges and the matching Alouette machines—that her anonymous “Carver” had been Roman all along. Embedded with Lieutenant Lark’s Sycamore Platoon, Iris recorded trench rules and soldier testimonies until a bombardment struck; Roman shielded her from a grenade, suffered shrapnel wounds, and was evacuated. Iris rode with a dying Lark and heard the Sycamores’ origin before returning to Avalon Bluff, where Roman’s bag spilled a blizzard of Iris’s preserved letters, confirming his identity as Carver; their confrontation gave way to confession, a first kiss, and, after hard days of digging graves and healing, a vow to choose each other.

As Dacre’s forces neared, Keegan returned to fortify the town, delivered proof that Forest was alive, and ordered contingency plans while Iris and Roman wrote side by side and decided not to flee. On the eve of Enva’s Day, Roman sought blessings from Marisol, Keegan, and Attie, and he and Iris exchanged swift vows in the garden, then spent a tender blackout night promising to keep their hands joined through whatever came. At dawn, eithrals bombed Avalon Bluff with chilling precision; the B and B inexplicably held as they aided the wounded, but a second wave dropped gas canisters. In the chaos, a masked rescuer led Iris away; she believed him Roman until his gait and the endearment “Little Flower” betrayed him as Forest, who dragged her from the field while the green cloud swallowed the limping, bloodied Roman.

Iris awoke in the woods, forced a return to the field, and found only blood and a ring drawn in the dirt before Forest pulled her east. Over days, Forest revealed that after being mortally wounded he had been healed and bound by Dacre at Meriah, fought under Dacre’s flag, and deserted to watch over Iris, wearing their mother’s locket he found in the captured trenches. Back in Oath, Iris resolved to stay with Forest for now while planning to find Roman, and in her old room discovered an unread letter beginning, “Iris! Iris, it’s me, Kitt.”

In the epilogue, Dacre surveyed the gas-hazed ruin of Avalon Bluff, spared it from fire, and sensed a stubborn will struggling to live in the golden field. Delighted to find a correspondent rather than a soldier, he ordered his servant Val to ring the ground and take the dying, raven-haired mortal below, then turned his gaze east toward Enva, leaving Iris’s search and the fate of Roman Kitt bound to the god’s designs.