Luther having a bad day, his wife truly leaves him. He witnesses a husband run off with diamonds leaving his wife to be gutted. Luther is in a church and confides in Alice, who he called that she was right. Alice renews his faith that while the universe is cold and harsh, love exists.
Episode six as Luther is questioning Alice on her state of mind.
Alice: What's wrong ?
Luther: Mind you, do you ever step outside yourself and wonder what you're doing and think you've gone mad?
Alice: No. Look, you and I are who we are. ( Steps closer to Luther)So I need you to know this John. Of all the people in the world..I would never betray you.
In series 2, Luther choosing to take Jenny in to protect her. By the end of the series, he's a full on Parental Substitute for her.
Series 3: "He's my mate and I love him." Naturally, this becomes a Tear Jerker when Justin is killed at the end of the episode.
The conversation between Alice and Luther in the Series 3 finale, where Alice finally makes her feelings perfectly clear to Luther. "I wanted something." "What?" "You."