While the whole family are delighted to have the young soldier back from Afghanistan, it soon becomes clear that he is hiding a secret.
Things start off well for Lee as he reconnects with each member of his family - which includes putting his younger brother Johnny (Sam Strike) at ease by revealing that he always knew about Johnny's sexuality.
Lee also has some luck with the ladies as he catches Lucy Beale's eye and ends up having a one-night stand with her.
Despite the happy homecoming, Mick (Danny Dyer) and Linda (Kellie Bright) are quick to realise that Lee is concealing something from them - and that Stan knows much more than he's letting on.
Mick's worst fears are later realised when he catches his son preparing to abscond with help from Stan (Timothy West).
Although Lee is initially reluctant to be honest with his father, he eventually breaks down and comes clean. Why doesn't Lee want to return to the army?
As announced in January, actor Danny-Boy Hatchard has been cast as Lee following his successful stint in the 20th anniversary revival of Jonathan Harvey's Beautiful Thing in the West End.
Hatchard said earlier this year: "I'm incredibly excited to be a part of EastEnders, a show that my family and I have watched for years.
"It's an honour to have the chance to share the camera with such talented actors and I can't wait to get cracking and join the Carter family."
EastEnders airs Mondays, Tuesdays, Thursdays and Fridays on BBC One.
Read our full spoilers for the next two weeks of EastEnders
Digital Spy Soap Scoop video - hit play below for gossip on the Christmas storylines in EastEnders, Coronation Street, Emmerdale and Hollyoaks this year.