Heartwarming / The Mystery of the Druids

• Despite all of his misguided and more than ethically questionable actions in the game, Halligan refusing to give up the case even after he's got no real reason to continue putting himself in danger is definitely heartwarming. Among more ambivalent, self-serving people like Lowry, his intent to solve the case can still be considered close to heroic.
• Halligan and Melanie seeing eye-to-eye to an extent, and Melanie getting to talk to someone (who clearly believes in her, even though he just met her) about rituals is surprisingly enjoyable.
• Though it comes at a rather odd place in the game, Melanie opening up to Halligan at Twelve Bridges. It's clear she hasn't had much time to talk to anybody like this in a long time. Even more so, the part where she tells him that he's become almost like a friend to her, in a way that suggests that it's rare.
• Mr. Blake! It's very clear he just wants to help out with his knowledge. Halligan actually listens to him intently, and it's a very welcome change from someone like the boss of the SLY. (Unfortunately, he does die initially, but he survives given the time travel at the end of the game)
• When it becomes clear that crossing Twelve Bridges is dangerous, Melanie is horrified that Halligan attempts to cross, clearly very upset about his lack of self-preservation and very upset that he doesn't seem to think much of it.
  Melanie: Don't you dare do that to me again, Brent!
• If Halligan/the player attempts to talk to Melanie again after she's already exhausted all her dialogue at Twelve Bridges, Halligan tries to egg her on to resume their "private conversation". When Melanie tells him that he's being pushy, Halligan seems legitimately downtrodden about it, but Melanie reassures him that it's nothing personal and that they'll have plenty of time to talk later in another situation. She doesn't belittle his social problems, regardless of why he has them. She clearly tells him he shouldn't do that, but also doesn't put him down for not understanding that at first, and it really shows that Melanie cares about Halligan.
• Absolutely everything about Halligan and Melanie's interaction at the library of the past, in the Monastery. Halligan really wants to ask Melanie out, but he's debating whether or not he should. Contrasting how forthright he was about his attraction to Janet, here he clearly realizes with her that he honestly has no idea how to handle it, and it's very nice that Melanie tries to help him out with it.
  Halligan: If we ever get out of here alive...Would you...I mean...Could you ever bring yourself to...
  Melanie: ...Go to Al's Pizza Palace for a pizza with you? Yes, I think I'd like that!
  Halligan: (Surprised) Hey! How did you guess?
  • Even better, Melanie reveals she found out about the Al's Pizza Palace thing because of Halligan's collection of empty pizza boxes in his incredibly unkempt office, and Halligan seems rather embarrassed about it. Melanie doesn't berate him for it, and seems to enjoy Halligan's excitement at her agreeing.
  Halligan: (Very enthusiastic) Right! It's a deal, then. I'll remind you about it!
  Melanie: (Laughing) Okay, Brent! I'm looking forward to it.
• Melanie refusing to go into detail about some of the things she finds in the ancient scrolls so as to not upset Halligan, who has already had a very unfortunate run-in with cannibals and technically become one himself unwillingly.