The Crawley family heads to London for Rose's presentation to society.
Mary's decision between suitors either becomes easier or more difficult, depending upon how you look at it.
Interesting information is discovered about Bates.
Mrs. Hughes and Daisy are called to London.
Edith has returned after eight months looking tired.
Tom and Edith are still praising Matthew's saving of Downton a year after his death.
Barrow asks Daisy to tell Baxter he's looking forward to what stories she'll tell him when she returns from London.
Lord Merton checks in with Isobel to see if she's attending Rose's ball with the hopes she is so he might change his mind to attend.
Rose and her friend Madeline meet the Prince of Wales, who knows Shrimpy, Rose's father.
Blake shows up to take Mary to an exhibition for lunch.
Barrow is upset that he has to call Tom sir when if he was still a servant Barrow would be above him.
Edith meets her Uncle Harold for the first time when he arrives with Grandma Martha.
Mary and Blake run into Gillingham at the exhibition.
Carson's ideas for a fun day for the staff don't excite Mrs. Hughes.
Tom runs into Sarah in town who drops some school papers into the street. He asks her to join him at the Grantham Arms for dinner.
Harold's valet let's Carson know his name is not Levinson, and Carson tells him he will be in their house.
Mr. Sampson the card sharp arrives at the Grantham dinner party with Rosamund.
Madeline and Harold dine together.
Ethan doesn't take easily to his tasks as a footman, and Carson isn't impressed.
Tom shows Sarah Downton Abbey. Barrow discovers them and makes Tom uncomfortable.
Rose asks Sampson to look after their bags while they dance and he helps himself to the contents.
Tom and Barrow continue to get under each others skin.
Isobel decides to go to Rose's ball and when she makes the decision she contacts Lord Merton.
Edith and Rosamund discuss Gregson, his business dealings and how to move forward.
Daisy learns Alfred has been kept on at the Ritz as a chef.
Violet and Isobel take of for London amid snarky conversation.
The Crowleys arrive at the palace for Rose's presentation amidst a parade of spectators.
Ethan talks to Carson about Daisy and Carson's face almost crawls off its skull.
The King speaks to Rose as she is presented.
Mrs. Hughes shares her discovery of a train ticket from York to London with Mary.
Mrs. Dudley Ward's love letter from the Prince of Wales was stolen from her handbag by Sampson.
Edith tells Rosamund that she has learned that Gregson got into a fight with some toughs his first night in Munich.
Mrs. Hughes gives Bates an opportunity to come clean, but he continues his lie about London.
Robert, Cora, Mary and Rose come up with a plan to burgle Sampson to get the letter before he publishes it and somehow makes a mockery of the Prince.
Harold takes a liking to Madeline, much to his surprise.
Mary tries to draw the truth out of Bates, but only gets a stare from him. Mary's conscience gets the best of her as she worries about the possibility he may have murdered a man, no matter what he did.
Ivy doesn't much like that Alfred isn't writing to her any longer.
Barrow tattles on Tom to Robert.
Baxter overhears Anna talking to Mrs. Hughes about Bates' pockets just before Barrow sits down probing for information. Molesley interrupts.
Ethan informs Daisy that Harold wants her to join them in America so that she can be his cook. Ivy overhears and looks jealous.
Mary, Rose and Blake infiltrate Sampson's suite to find the stolen letter. They're unsuccessful.
Mary wonders why Blake would still be interested in her when his lot is going down and his is going up, but he's interested in the future.
Bates' criminal past comes in handy when he helps Sampson on with his coat and retreives the elusive letter.
Mary decides to burn the train ticket stub when she realizes how loyal Bates is to the Crawleys.
Rose's ball begins and the Prince of Wales steps in to open the ball by giving Rose her first dance.
Mary chooses to hide with Gillingham rather than let him hand her over to someone else to dance with.
Gillingham breaks the news to Mary that Blake is set to inherit one of the largest estates in Ulster. Suddenly Blake is more eligible than Gillingham.
Mary returns to the ballroom and dances with Blake.
Edith and Tom talk and she decides to return to Downton immediately.
Mary asks Blake why he didn't tell her about his impending inheritance. He wanted to win her based on his merits and not his position.
Edith decides to use the Drewe family to raise her daughter after all. She attempts to keep her story secret, but Mr. Drewe seems aware of the situation. He decides to send a letter to himself and act as if an old friend died, leaving the child in his care.
Baxter tells Molesley that his strength has made her strong.
Daisy decides not to go to America, but Ethan tries to persuade her to go because he likes her. Instead, Ivy asks if she can go in Daisy's place.
Daisy was so chuffed about Ethan liking her she wanted to kiss him but was afraid it would give him the wrong idea.
Carson balks at walking into the ocean and Mrs. Hughes offers her hand. The two walk into the water together.