In London, 1908, Agnes Tower, who works at Gamages department store, finds her life about to change following an encounter with Harry Gordon Selfridge. He is finalising his great plans for the biggest and finest department store the world has ever seen in Oxford Street. His family also show up in London from Chicago. Word about the impending store opening begins to spread around London, and Agnes approaches Harry for a job. He remembers her, and agrees to give her a job. Opening day is a great success, attracting huge crowds but the takings are not brilliant.

Medan Harry arbetar med ett nytt projekt blir en modevisning i butiken en stor utmaning för personalen.

Ett smink- och skönhetsevent får Londons damer att bli upprörda, och Harry möter en gammal fiende.

Det går utför för Ellen Loves karriär både på Selfridges och med Mr Selfridge. En vacker ballerina vid namn Anna Pavlova gör entré i varuhuset. Mrs Selfridge fortsätter med besöken i konstnärsstudion. Och Agnes alkoholiserade far fortsätter att ställa till det.

Harry planerar att ställa en modern automobil i ett av Selfridges skyltfönster. Porträttet på Mrs Selfridge är färdigt och levereras direkt av konstnären. Mr Selfridge vädjar till en skamsen Agnes att hon ska komma tillbaka till varuhuset. Miss Love har svårt att acceptera brytningen med Harry.

Harry is left unconscious after the car accident and as his family gathers by his bedside, the news arrives that Mrs Grove is dead - something which leaves Miss Mardle confused. Meanwhile, a suffragette demonstration in the area sees all the store's staff pulling together, and as Victor and Lady Mae conduct their secret affair, Agnes and Henri's friendship continues to grow.

Author and spiritualist Arthur Conan Doyle is in Selfridges for a Sherlock Holmes book signing when he persuades Harry to hold a seance in the store - and the results of the gathering force the retail magnate to have a long-overdue heart-to-heart with Lois. Meanwhile, Agnes is transferred to women's fashion, Doris resolves to help an old friend, Miss Mardle is still agonising over Mr Grove, and Kitty has a secret admirer.

Harry får besök av en gammal vän från USA som också visar sig vara en presumtiv konkurrent, Mr Woolworth. Mr Selfridge inser att något nytt måste hända i varuhuset. Victor fortsätter att drömma om en egen restaurang medan Agnes och Henri trivs i varandras sällskap.

Lady Mae arranges an after hours shopping spree for King Edward VII. To thank Harry, the King invites the Selfridges to the opening of Ellen Love's new play, much to Rose's dismay. The Selfridges and Lady Mae discover the play is a satire aimed at ridiculing them, and scripted by an embittered Frank Edwards. Ashamed and humiliated, Rose takes the children back to America. Meanwhile, wedding bells will soon be ringing for two of Selfridges' own.