In the kingdom of Cloister, Jack, a young farm boy is fascinated by the legend of Erik, an ancient king who defeated an army of invading giants from a realms in the sky by controlling them with a magical crown. At the same time, Princess Isabelle becomes fascinated with the same legend.
Ten years later, Jack goes into town to see his horse to support his uncle's farm. There, Jack spots Isabelle and develops a crush on her, after defending her honor from a group of thugs. Meanwhile, Lord Roderick returns to his study, only to find that he has been robbed by a monk. The monk offers Jack some magic beans that he stole from Roderick as collateral for his horse, Back at the castle, Isabelle quarrels with her father, King Brahmwell, as she wants to explore the kingdom, but he wants her to marry Roderick. Likewise, Jack's uncle scolds him for being foolish before throwing the beans on the floor and leaving the house with some of Jack's parents personal things to sell in town.
Determined to be free, Isabelle sneaks out of the castle and seeks shelter from the rain in Jack's house. As it rains, one of the beans takes root and grows into a massive beanstalk that carries the house and Isabelle into the sky as Jack falls to the ground with Isabelle's bracelet.
Jack, Roderick, and Roderick's attendant, Wicke, volunteer to join the king's knights, led by Elmont and his second in-command, Crawe, and climb the beanstalk in search of Isabelle. As they climb, Roderick and Wicke cut the safety rope, intentionally killing some of the knights. At the top, they discover the giants' realm and decide to split into two groups; one with Jack, Elmont and Crawe, and the other with Roderick and Wicke, but not before Roderick takes the remaining beans from Jack ( although Jack manages to save one for himself).
Jack's groups is trapped by a giant, who takes everyone prisoner except him. Meanwhile, Roderick's groups encounters two other giants, one eats Wicke but before they can do the same to Roderick, he puts on the magic crown.
Jack follows the giant to their stronghold, where Crawe has been killed by the two-headed giant leader, Fallon, and finds Isabelle and Elmont. As the giants prepare to kill the rest of their prisoners, Roderick walks in and enslaves the giants with the crown. He tells the giants that they will attack Cloister at dawn and allows them to eat Isabelle and Elmont. Jack rescues Isabelle and Elmont as one of the giants prepares to cook Elmont as a pig-in-a-blanket. The trio makes for the beanstalk, where Jack causes the giant guarding the beanstalk to fall off the realm's edge. Seeing the giant's body, Brahmwell orders the beanstalk cut down to avoid an invasion by the giants.
Jack and Isabelle head down the beanstalk, while Elmont stays to confront Roderick. Elmont kills Roderick, but Fallon takes the crown before he can claim it and is forced to escape down the beanstalk. Jack, Isabelle, and Elmont all survive the fall after the beanstalk is cut down by the king's men. As everyone returns home, Jack warns that the giants are using Roderick's beans to create beanstalks to descend down to Earth and attack Cloister.
The giants chase Jack, Isabelle, and Brahmwell into the castle, where Elmont fills the moat with oil and sets it on fire. Fallon falls in the moat and breaks into the castle from below. As the siege continues, Fallon captures Jack and Isabelle, but Jack throws the final bean down the giant's throat, causing a beanstalk to rip apart his body. Jack takes the crown and sends the giants back to their realm.
Jack and Isabelle marry, and tell the story of the giants to their children. As time passes, the magic crown is crafted into St. Edward's crown and is presently being held in the Tower of London. At the end of the movie, Roderick's kin smiles at the crown.
In all honesty, I thought this film would bore me to tears but it actually surprised me. The film was entertaining and interesting. The special effects were flippin' awesome also. This movie critic gives this film 5 stars all the way around.