Albert Markovski (JASON SCHWARTZMAN) is a young man facing several crises. First is the fact that the members of his environmentally friendly Open Spaces Coalition -- of which he formed the local chapter -- are now being swayed by the far more slick and charismatic Brad Stand (JUDE LAW). The fact that he works for the ever-expanding Huckabees retail store corporation doesn't seem to bother anyone but Albert.
Then there are the various coincidences in his life -- some of which involve repeatedly seeing the same lanky Nigerian man -- that are about to drive him crazy. Thus, and after happening to find their business card in a borrowed jacket, he calls Bernard (DUSTIN HOFFMAN) and Vivian Jaffe (LILY TOMLIN), a team of married existential detectives who agree to take on and discover the cause of his dilemma.
Following various experiments, they team him up with fireman Tommy Corn (MARK WAHLBERG) who's facing his own existential crisis regarding anything related to petroleum. It's gotten so bad for him that his wife has taken the kids and moved out, but the Jaffes are more concerned with their archrival, the ever pessimistic Caterine Vauban (ISABELLE HUPPERT), influencing the two men.
When Brad gets wind of the Jaffes, he decides to hire them for himself, all of which occurs as his live-in girlfriend and current model face of Huckabees, Dawn Campbell (NAOMI WATTS), has decided to forgo any sort of beauty regimen. As the detectives try to do their work, their subjects attempt to understand and do something about all of the strange things happening in their lives.