Jack McCall (Eddie Murphy) is a literary agent who uses his mouth to get various book deals, and isnt afraid to stretch the truth to get them. While trying to get a book deal from a new-age self-help guru named Dr. Sinja (Cliff Curtis), the Boddhi sees through the lies and curses Jack by magically appearing in his backyard with 1000 leaves. Jack was sent a catalog by Dr.Sinja and demands an explanation also include the Boddhi Tree. Dr.Sinja goes to Jack's house and explains that for every word that Jack says, a leaf will fall off of the tree. When the tree runs out of leaves, the tree will die, along with Jack. In time, he finds that even written words count towards his limit, plus anything that happens to the Tree will also affect Jack. When Jack tries to cut it down with an axe, an axe wound appears on him. When squirrels climb the tree, it tickles him. When a gardener tries to poison it with DDT, Jack gets high on the fumes.
With Jack forced to pick and choose his words, communicating with others becomes difficult and full of misunderstandings. These misunderstandings cost him two book deals, his job, and his wife Caroline (Kerry Washington). She walks out on him when she thinks his sudden silence is due to him not loving her anymore. When he tries to explain the tree to her, she doesnt believe him. Only Jacks assistant Aaron (Clark Duke) realizes he is telling the truth, and goes to Jacks house to keep track of how many leaves are remaining.
With his life falling apart and the tree running out of leaves, Jack goes to Dr. Sinja and asks how to end the curse. The guru tells him to make peace with all of his relationships. With just one branch of leaves left, Jack tries to reconcile with Caroline, but shes still hesitant towards him. He visits his mother (Ruby Dee), who lives in an assisted living center and has dementia. She tells Jack who she thinks is Raymond, Jacks late father that she wishes Jack would stop being angry at his father for walking out on them when he was a kid. Jack, realizing that this is the relationship that needs the most mending, goes to visit his fathers gravesite. With only 3 leaves remaining, Jack forgives his dad. With 0 leaves remaining, Jack collapses and appears to have died.
Jacks cellphone rings, and its Aaron. He tells him that the trees leaves have magically reappeared. Jack, who is still alive, asks if any leaves are falling off, and they are not. Jack can now talk freely again. It works and they get back together. He doesnt get his job back (Aaron was promoted to Jacks old position), but he wrote a book about the experience and gets Aaron to make the deal. Aaron later receive a branch of the Boddhi tree when his new assistant Steven informed him that there is a delivery for him, resulting to Aaron being shocked at the moment.
Jack makes a last ditch effort to get back Caroline by buying the house she always wanted and he did, they both smiled as their child spoke his very first words "boom".