Preparations for the wedding were problematic. The building where the wedding was planned to take place was being demolished causing Emily to freak out, Ross and Monica's mother and father Judy and Jack Geller and Emily's father and stepmother Stephen and Andrea Waltham were not getting along because the Gellers refused to pay for the Walthams's wine cellar.
Before the ceremony began, the parents continued fighting until Ross stepped in and threatened not to have grandchildren with Emily, so they stopped.
Rachel stormed in, unnoticed by Joey who was making out with one of the bridesmaids Felicity (the other bridesmaid being Monica) and sees Ross and Emily kissing and decides not to tell Ross she loves him, but instead gives him her blessing and gives him a hug.
The ceremony began with musicians playing and Felicity walking down the aisle with one of the best men, Joey with Andrea, Monica with Chandler and Emily with Stephen. Emily then says her vows with no problem, but when Ross says his, instead of saying "I, Ross, take thee, Emily", he says "I, Ross, take thee, Rachel", then there comes a look of shock on his face, then Emily's, then Rachel's, then Monica's, then Joey and Chandler's and then Phoebe's. Ross then tries to correct himself by saying "Emily" and the guests are shocked too, mostly Rachel who had been crying. The vicar asks if he should go on and Rachel is left shocked, confused and thoughtful: "Does Ross still love me???", she wonders, putting an end to Season 4 and leaving a cliffhanger.
In the Season 5 premiere, the wedding scene picks up from where the Season 4 finale left off with the vicar about to marry Ross and Emily. It cuts to Ross making the mistake the vicar asking if he should go on and then the rest of the plot begins. Rachel asks the woman in the front "He said 'Rachel', right? Do you think I should go up there?" then Emily tells the vicar to go on. They start again and then Ross this time gets it right, but Emily glares. Emily forcefully places the ring on Ross's finger then Ross places another ring on Emily's finger. The vicar tells Ross that he may kiss the bride, but Emily refuses until Ross manages to kiss her on the cheek. They are declared husband and wife and the musicians play while the newly married couple walk out of the chapel and Emily pulls her arm away from Ross's and tells him to just keep smiling and Ross says "Okay.". Once they are out of the chapel, Ross closes the door and says to Emily "That, uh, that was pretty funny, wasn't it?" and then she socks him in the stomach.
At the reception, Emily is yelling at Ross in the bathroom and then Ross comes out but Emily stays inside. After a small talk with Joey and Rachel, he finds that Emily has escaped through the bathroom window, something Rachel had done too.
At the hotel, Emily's parents come to collect Emily's things and Stephen tells Ross that Emily is in hiding, is utterly humiliated and doesn't want to see Ross ever again and Andrea then tells Ross she thinks he is delicious. Ross then tells Stephen that he (Ross) and Emily are meant to leave for their honeymoon and tells Stephen that she'd better be at the airport and that saying Rachel's name did anything because she's just a friend and that he loves Emily and that he can't imagine spending his life with anyone else. Stephen promises to tell Emily. At the airport, Ross finds Rachel and when Emily doesn't show up, Ross decide to take Rachel with him instead, but as soon as Rachel boards the plane and Ross gets his jacket which he left behind, he finds Emily who notices Rachel got on to the plane and Ross says "Oh. No, no, no." She then runs away and Ross chases after her, leaving Rachel alone on the plane to Greece.
Ross tries many attempts to reconcile with Emily, but ends up failing miserably until he manages to p contact her and tries to convince her to forgive him over the phone. Emily agrees to come to New York, only if Ross never sees or speaks to Rachel again. This upsets Ross and the rest of the gang.
In "The One With The Yeti", Emily wants Ross to get rid of all the furniture Rachel has touched, used, sat on, slept on etc. and is selling them. Later, one night during dinner at Monica and Rachel's apartment", Emily calls and Ross tells her Rachel is there. Emily is then furious, but Ross tells her he can't stay away from her. Ross asks Emily if he can trust her and Emily responds "No.", thus leading to the end of Ross and Emily's marriage.