In a storm off the Victorian coast in 1892, a young English girl is shipwrecked and orphaned. She is rescued heroically by the only other survivor of the wreck, who is feted and rewarded in Melbourne. The girl is taken in care by her guardian who has made a meager fortune from gold, and settled at Echuca — the great Australian inland port on the River Murray. His ward is sixteen years old, and her name is Philadelphia Gordon. She is known as Delie. Delie is an energetic and high-spirited girl who wants to paint, and not conform. She finds it difficult to understand why her aunt Hester, a tart and unsmiling woman, seeks to impose her ideas of womanhood, femininity, even good housekeeping on a girl who needs nothing more than the freedom to lead her own life. It is her cousin, Adam, who truly awakens in Delie the feelings of young womanhood.

Tom Critchley, the seaman who rescued Delie, arrives in Echuca on a paddle steamer he bought with his reward. It is the beginning for Delie of a remarkable ten years in her life. Her investment of part of her inheritance in the riverboat is, without her knowing it, the first step towards a turbulent marriage to a riverboat man and, indeed, to the boats who ply their great trade along the mighty, unpredictable and perilous river.

Delie quickly attracts the attention of the town gossips, living alone in a ladies boarding house. Luckily, she finds work hand-colouring photographs. Delie is trying hard to ignore riverboat labourer Brenton Edwards who is working even harder to draw her attention. Tom sells another share in the paddle steamer, this time to Brenton, making him and Delie business partners, much to her chagrin. Uncle Charles brings word of Aunt Hester's failing health. Delie returns to see her aunt on her deathbed but despite Hester clearing Delie of any blame for Adam's death, her last words to Delie are that she can never forgive her. Delie has no desire to stay on with her uncle and joins Brenton and Tom on the Philadelphia.

Ben informs Delie of troubles on Uncle Charles' farm but he puts on a brave face when speaking with Delie. Tom finalises the deal which puts Delie and Teddy into partnership as the new owners of the Philadelphia before departing for a new ship sailing the high seas. Brenton prepares an intimate dinner for Delie. Delie meets Bessie's friend Julia but when Brenton seems receptive to Julia's advances, Delie packs up and moves to Melbourne to continue her art education. Delie receives an offer to travel overseas from her patron, Alistair Raeburn, but Brenton makes a surprise appearance and proposes marriage. Delie's refusal to give an answer sends Brenton back to Echuca. Delie follows him only to learn he has already departed on a long voyage. Borrowing Bessie's horse and buggy, Delia chases after the Philaelphia and accepts Brenton's proposal.

Delie and Brenton are to wed, and while the crew scrub down the the Philadelphia in readiness, Delie pays a visit to see her Uncle Charles. Ben is gone and both Charles and the property are looking run down but Delie lifts his spirits. Delie and Brenton are married in a riverboat ceremony. Brenton accepts a bet from George Blakeney to see whose riverboat is fastest. Ben surfaces in Echuca and explains to Delie he left her uncle's farm because Charles never paid him. Brenton has no room for him on the Philadelphia so Delie finds him a job as a deckhand on Providence, George Blakeney's boat. After many trials and tribulations for both boats, Providence comes out ahead in the race. Brenton accepts a risky but high-paying job running cargo up the Darling in low river levels.

Stranded for three month by low water levels in the Darling River in the midst of a drought, the Philadelphia and her crew make the best of their situation in the hope that rains will wash down from Queensland and allow their escape. Their wait is complicated by Delie's pregnancy and the deadline it brings but they find some relief when they meet the couple whose land they are on. The conflict between Brenton's new hire, Steve Farrell, and the Philadelphia's cook, Ah Lee, ends in gunfire and Ah Lee flees into the bush. Robert survives the shooting but Brenton gives him his walking papers. Needing a new cook, Delie is the men's obvious choice despite her lack of culinary skills. Fortunately, Ah Lee returns. Delie's friendship with Mrs. Slope is marked by Delie's anticipation of her first child while Mrs. Slope still struggles to deal with the tragedy of losing her two children. Jim discovers a group of men have dammed the river upstream of the Philadelphia.

Two years have passed since the destruction of the Philadephia. Brenton is working at the redgum mill dreaming of rebuilding the Philadelphia while Delie resumes her old job of colouring postcards. After Brenton loses his job, Delie and son Gordon move to Melbourne where she reconnects with Alastair Raeburn who agrees to sponsor her work. Delie's friend Imogen believes Alastair is interested in more than just Delie's art and she is proven right when Alastair eventually professes his love for Delie. Brenton turns to sly-grogging to finance the rebuilding of the Philadelphia while Ben departs to join to the army. Ben stops in Melbourne to see Delie but sees how much she has changed since leaving Echuca and is worried she won't be going back. With reconstruction of the Philadelphia underway, Brenton takes a job with George Blakeney. Delie departs suddenly from Melbourne and returns to Echuca but her reunion with Brenton is cut short when he is critically injured in a riverboat accident.

Brenton's accident and subsequent paralysis inspires Delie to turn her talents towards being a riverboat captain. Alastair resurfaces in Echuca but his enthusiasm for Delie and her art is matched by her desire to stay in Echuca. Alastair agrees to sell Delie's paintings and she uses the profits to finance the rebuilding of the Philadelphia. The crew is reassembled and the Philadelphia begins running cargo again. Alastair appeals for Delie to accept a scholarship that will allow her to study in Europe but Delie turns down the offer (and Alastair) to stay with her husband on the Murray RIver. Delia earns her Master's Ticket but work is at short supply at the Philadelphia is in debt. Ben returns from the war. Delie takes on a risky, time-sensitive job hauling wool that pushes the Philadelphia and her crew to their limits.