Hungry for wealth Fletcher Reede (Jim Carrey) will stop at nothing to get partner or win his cases. When Miranda (Amanda Donohoe), one of the firm's partners discovers Reede's ability to lie to win a case, she puts him on a high profile divorce case. Unfortunately for Fletcher the court date is the same day as his son Max's (Justin Cooper) birthday party. Lately Fletcher has been neglecting his obligations to his son because he is allowing work to get in the way. He promises that he will be at Max's birthday party the following day.
Trying to move on after their divorce, Audrey (Maura Tierney), Fletcher's ex-wife, has started a relationship with Jerry (Cary Elwes). Jerry and Audrey's relationship appears quite dull but Jerry is a great father figure to Max.
Samanta Cole (Jennifer Tilly) becomes quite impressed with Fletcher when he meets with her regarding her divorce case. Miranda is equally impressed and promises him partner if he wins to big case. Miranda is so taken with Fletcher that she makes her move on him and they end up spending the night together causing Fletcher to miss his son's birthday party.
Max becomes so disappointed with his dad that he makes a wish that his dad can't tell a lie for an entire day. When his wish is granted it turns Fletchers world upside-down. Fletcher's travels through the office and courtroom are extremely entertaining as he tells everyone he sees just what is on his mind because he is unable to tell a lie. Samantha's court case gets extremely difficult however because Fletcher knows he is defending someone he doesn't believe is being honest. He tries numerous times to get the trial postponed but is unable to lie about why he needs the case delayed.
The bright side of Fletcher's day of honesty was the he discovers how much he truly loves his son. Because of his neglectfulness toward his son, Fletchers ex-wife Audrey has agreed to move to Boston with Jerry and take Max with her. Fletcher makes one final attempt to show his son how much he means to him in a wild scene which will make you laugh.
If you are looking for some laughs along with a great story check out Liar Liar. The message of the film is a good one and the characters were very well cast. Liar Liar is one of the funnier Jim Carrey comedy films as it allowed him to display his physical comedy talent. The combination of Tierney, Carrey and Cooper provided a great family comedy team. Justin was nominated for a Young Artists Award for his role as Max.