Fraser belongs to an exquisitely eccentric Scottish family living amidst an idyllic old estate, Kiloran House, which is now under the strict control of the indomitable Gamma Macintosh (Rosemary Harris). Though the child and animal -filled estate is kept remotely sane by both Gamma and Fraser's mother, Moira (Mary Elizabeth Mastrantonio), it is spiritually headed by Fraser's madcap father, Edward (Colin Firth). Edward is an inventor, misunderstood genius and the founder of the only moss factory on the entire European continent. To others, he is a crackpot. But to Fraser, he is a force beyond comprehension. Life with father on the Macintosh estate is a fairy tale, a series of one remarkable occurrence after another, filled with ingenious contraptions and amazing figments of the imagination.
Then, reality strikes in the person of Uncle Morris (Malcolm McDowell), the sole heir to Gamma's estate and a hard-nosed businessman who has had his fill of Edward's hare-brained schemes and moss factory. Morris brings with him to Kiloran an enchanting outsider: his alluring French fiancee Heloise (Irene Jacob) who will alter the family's relations and fate forever. Everyone falls madly in love with Heloise, including Fraser. But as the fearless Fraser watches the way Heloise takes Kiloran by storm, he begins to see the world - and his incorrigibly boyish father - through newly adult eyes.