Nick Sullivan - Luka Dokich

Luka Dokich, played by Keelan O'Hehir, made his first on-screen appearance on 14 September 2004. Luka is Liljana Bishop's son, who was adopted at birth. Luka comes to Erinsborough to meet up with his grandmother and ends up meeting his real mother and half sister.

Model O'Hehir received the script to audition for Neighbours through his agency. O'Hehir described his character's connection with Serena Bishop (Lara Sacher) as "instant". He said "There's a really amazing chemistry between them." O'Hehir explained that Luka's upbringing has not been easy and that he has been through "a lot of stuff". He added "He's had this inkling his whole life that something is not and his confusion comes through in his behaviour." Luka later begins an incestuous relationship with his half-sister, Serena. They are unaware that they share the same mother. This was the second time Neighbours had depicted an incest storyline.

Luka is the product of a brief relationship between a teenage Liljana Ristic (Marcella Russo) and Ivan Petrovic. Liljana's mother, Svetlanka (Deidre Rubenstein), gives Luka to the Dokich family and pays a doctor to tell Liljana that her baby is dead, so she can save her family from any embarrassment. Svetlanka becomes Luka's godmother. Luka feels out of place within his family and becomes convinced that he is adopted. After he becomes obsessed with a female teacher and she ignores him, Luka sets fire to her bag and it spreads to the school. Svetlanka provides him with a false alibi when he turns to her for help. Luka goes to Erinsborough to find Svetlanka and she tells him that he is not adopted and that he should go home. Luka begins to develop a relationship with Serena Bishop. Svetlanka tells Luka that she spoke to a nurse from the hospital where he was born, and she confirms that he is not adopted. Luka does not believe her and he hides in an old storage shed, with Serena being the only person who knows he is there.

Luka and Serena grow closer and he tells her about the fire he started. Serena later decides that she wants to lose her virginity to Luka, but before she does, she receives a call telling her that her mother, Liljana, was in hospital. Liljana requires a liver transplant and Svetlanka tells Karl Kennedy (Alan Fletcher) that Luka could save Liljana. Svetlanka tells the rest of the family that Luka may have the same blood. Sky Mangel (Stephanie McIntosh) uses a radio to put out a call for Luka and he hears the message and goes to the hospital. Luka is a match and he is taken into surgery. Svetlanka sees Serena and Luka together and tells Serena the truth about her half-brother. Just as Luka goes to leave town, Serena blurts out that Liljana is his mother in front of her family.

Luka is happy that he has found his mother, but Liljana struggles to find any feelings for him. Luka and Serena become friends and Liljana and Luka get to know each other. Liljana's husband, David (Kevin Harrington), finds the situation difficult and Serena finds it hard to share her mother with Luka. Liljana invites Luka to move in with them, but David tells Liljana that Luka cannot be trusted. Luka wants to find his real father, but he discovers that Ivan had died. When he hears Liljana tell David that she did not love Ivan, Luka takes David's suitcase and burns it. Serena confronts Luka when the suitcase is returned and eventually persuades Luka to return to Perth and get some help. Liljana tells him that she loves him and he leaves.