After being phone buddies for months, Gavin and Stacey finally arrange a rendezvous in Leicester Square, with Stacey's best friend Nessa and Gavin's pal Smithy coming along for support.

After a huge misunderstanding on the phone, Stacey thinks Gavin is finished with her. He drives to Wales to explain and ends up taking her home with him.

Gavin and Stacey announce their surprise engagement, much to Gavin's parents' delight. However, Smithy is not happy and refuses to talk to Gavin.

The Shipman's and Smithy travel to Barry Island for the wedding preparations; Gavin has to choose between the horse and carriage that Stacey wants or the Bentley that he wants; and Nessa thinks she might be pregnant.

Stacey's brother Jason arrives home early, much to Uncle Bryn's horror. Stacey has her hen night, and Gavin has two stag nights, the second of which reveals something about Stacey that could jeopardise the whole wedding.

The wedding day has finally arrived, but whether they will go through with it is another matter; Uncle Bryn may finally admit what happened on the fishing trip; Nessa is conflicted.