When Colin Farrell was doing press for the first season of the detective series Sugar, he had to be very careful with how he spoke. Sugar is a story about a quirky private detective, but it’s also secretly a work of science fiction, something that doesn’t become clear until halfway through the season. “I knew that I could get the show in deep shit if I revealed certain things,” he tells me. Now as Sugar heads into its next season, which starts streaming on Apple TV on June 19th, Farrell says he feels “unburdened” by the previous veil of secrecy. “There are certain things I wouldn’t mention here about season 2,” he says, “but nothing as big a clanger as the reveal of episode 6 of season 1.”

Spoiler warning for the first season of Sugar.

That secret is that Farrell’s character, a loveably strange private detective named John Sugar, is actually an alien. And he’s an alien obsessed with old films, which gave him a rose-tinted view of humanity, and contributed to his notable quirks, like never leaving the house without a suit and tie and, for some reason, being beloved by all dogs. At the end of season 1, Sugar’s fellow extraterrestrials had fled the planet after being discovered for what they were, thus putting their lives at risk. But John stayed behind, in part to deal with some unfinished business involving his sister, who went missing on his home planet. But he also just really loves humans, and doesn’t seem ready to leave them, and his ’66 Corvette Sting Ray, behind.

At the outset of season 2, John takes on a new case involving the missing brother of an up-and-coming boxer, which sends him into some of the seedier areas of Los Angeles’ underground drug trade. At the same time, he’s slowly learning more about what happened to his sister and also dealing with the fallout of being isolated from the rest of his species. Every so often he sends out a message on an alien communication contraption, but only receives silence in return. This all forces John to confront a number of largely new experiences for him: loneliness, violence, and, eventually, even love. For Farrell, it’s that element of growth that makes Sugar’s latest venture so interesting.

“Even though the character is from where he’s from, it was always a device, a contrivance used to try to explore the human condition,” he explains. “Season 2 is a case of honoring the character foundation that we had established, and also adding to it, and putting Sugar in situations where new parts of himself were going to be exposed and he was going to be challenged, he was going to have the opportunity to feel things that he hadn’t felt before, and be confounded as to what to do with those feelings, whether it’s in relation to romantic love, or in relation to violence. None of us really know what we’re capable of until we’re in a situation where we have to respond to a particular event or environment. And it’s the same for Sugar.”

That said, the season does answer some important questions about John’s extraterrestrial origins, though I won’t spoil anything just yet. But the most interesting thing about the continuing story is the way John grows as, well, a person. He’s still a great detective and tirelessly thoughtful friend, but he also messes up, makes poor decisions, and does things that go against his beliefs in order to help others.

After spending so much time on Earth, especially now that he’s isolated from his own kind, John is becoming that much more like the humans he’s so infatuated with. And through that he becomes much more vulnerable. In fact, one particular moment in season 2 offers perhaps the most intimate look at John so far: he’s not naked or hurt, but wearing jeans and a sweatshirt, a far cry from his typical detective uniform.

“It genuinely was a little bit strange,” Farrell says. “Out in the world in jeans and a sweater, it felt a little other.”