Having experience with Australian immigration process, I’m into anything that highlights how draconian it is. That said, the logline is a bit convoluted. I would simplify it. I don’t think the secondary characters need to be included, as it makes the logline confusing to read. A logline should sell the pure essence of the story, the central idea, and it doesn’t need too much information.

“When she tries to learn more about the mysterious circumstances of her husband’s death, an ocean-loving immigrant from Sweden, who has recently arrived in Sydney, uncovers the dark underbelly of the immigration system, putting both her and her new friends all in danger in the process.”