During his time on the show, Danny is involved in several plot lines that contribute to his strained relationship with both Jake and their boss Johnny Allen (Billy Murray).

Danny Moon first arrives in Albert Square - the community of Walford, a fictionalized borough in East London - in late December 2004, along with his older brother Jake (Joel Beckett).

He nevertheless allows Jake and Danny to stay at his house in exchange for helping him and his younger brother Spencer (Christopher Parker) look after their grandmother, Nana (Hilda Braid).

After ordering them to remain in Walford for further examination of their progress, Johnny arranges for Jake and Danny to work for the square's gangland kingpin - Andy Hunter (Michael Higgs).

His attempts to calm down over the situation lead to Danny having a brief relationship with Andy's estranged wife, Sam Mitchell (Kim Medcalf).

On New Year's Eve 2005, Johnny contacts Danny and orders him to murder Andy's best friend, Dennis Rickman (Nigel Harman) - who had severely beaten Johnny in retribution for killing Andy and threatening to harm Dennis' wife Sharon Watts (Letitia Dean).

When Johnny gets ambushed by the Mitchell Brothers, he asks Danny to look after his daughter Ruby (Louisa Lytton) while he deals with Phil and Grant alone.

Danny's behavior then shows signs of mental illness when he refers to Johnny as "dad" when asks Ruby if he ever talks about him.

After a short struggle, Danny knocks Jake unconscious with a baseball bat and - under Johnny's orders - marches the Mitchells into the nearby woods armed with the shotgun and a spade with the intent to kill and bury them.

[4] After confessing that Danny was the one who stabbed Dennis on Johnny's orders, Jake buries his brother in the woods - using the spade to mark his grave - whilst Phil and Grant rush out to confront Johnny, only to find that Ruby has already forced her dad to turn himself in for the murders of Andy and Dennis.