Set in Sydney Australia the story revolves around Leon (Anthony LaPaglia) a police detective in his mid-40s who is married with two teenage sons. He struggles to keep his life under control but feels it slipping away from him especially after he has a fling with a woman Jane (Rachael Blake) whom he meets in a dancing class he is taking with his wife Sonja (Kerry Armstrong). Jane is also surviving the breakup of her marriage to Pete (Glenn Robbins) and is simply lonely. She lives next door to Nik (Vince Colosimo) and Paula (Daniela Farinacci) a young couple with three children who seem to have a strong and happy marriage even after certain events nearly tear it apart. Sonja on the other hand suspects her husband is cheating and talks to her therapist Valerie (Barbara Hershey) about it. Valerie urges Sonja to confront Leon and tell him her feelings. Meanwhile Valerie and her husband John (Geoffrey Rush) are having problems of their own trying to come to grips with the murder of their young daughter a few years before. Somehow the lives of these eight people intersect when Leon becomes embroiled in a missing persons investigation.
For the most part the ensemble cast of mostly Australian actors is quite excellent. Many might not know the fact that LaPaglia who usually plays tough Italian New York types (One Good Cop So I Married an Axe Murderer) is actually a native Australian. Hearing his lilting and natural accent is refreshing and he gives his best acting effort yet as a man in the throes of a midlife crisis. Armstrong also turns in a quiet and subtle performance as the wife Sonja who eventually understands her husband's turmoil even though it wounds her deeply. Hershey and Rush play well off of one another as the damaged couple knee-deep in the grieving process particularly Hershey who gives an interesting twist on a successful therapist spiraling into her own self-doubt and despair. She proves once again how great an actress she really is. The other supporting characters lend depth to the story with Colosimo and Farinacci as Nik and Paula standing out the most. Their intense love affair starkly contrasts the messed-up lives of the rest of the couples.
Lantana refers to a type of plant which is filled with beautiful and exotic flowers but hides a thick thorny growth underneath. The opening shot takes us from the middle of this thorny bush where we see what appears to be a body entangled in it and pans out in a strange and slow way to show a great vista (reminiscent of David Lynch's opening to Blue Velvet). This pretty much sums up the feel of the movie--strange and slow--but not always in a positive light. While the performances are all good the pacing and subject matter brings the film down. The actions of the characters aren't always enough to keep up the momentum and the only compelling parts are when the actual mystery of the investigation start to unfold. You aren't sure who's guilty and who's not and the movie keeps you guessing until the very end. Yet the meandering personal dramas begin to get stagnant. Watching dysfunctional people deal with their marriages is something we've seen many times before.