Comics

In the comic Fiona and Shrek just got married and are just heading towards their hotel to celebrate their honeymoon. However Lord Farquaad is back in the land of the living as a ghost and tries to foil their attempt, thinking he should be the one to marry Fiona to become king, but to do so he must kill her first. He uses his trusty torturer thelonious for this task, he kidnaps Fiona and ties her onto a raft heading for a waterfall. Donkey, Shrek and dragon manage to save her and scare Lord Farquaad away, so the honeymoon could finally begin.

Movie

Princess Fiona is the wife of Shrek, she hasn't always been an ogre. She had a spell put on her by an evil witch when she was a young girl, when the sun set she was turned into an ogre but when the sun rose once more she was turned back into a beautiful young woman. She would forever remain this way unless she would be kissed by her true love, only then would she forever remain in her true form. Her parents, king and queen of Far Far Away, decided it would be best to lock her up in a deserted tower guarded by a dragon so she could be rescued one day by her true love.

And so she was, but it was hardly the Prince Charming she had hoped for. Instead it was the ogre Shrek and his sidekick Donkey. There she was told by Shrek that Lord Farquaad was waiting to marry her so he could get his swamp back. After they travel together they begin to develop feelings for each other, but thanks to a misunderstanding they fall apart. She stood ready to marry Lord Farquaad until Shrek broke through the door of the church announcing to everyone that he loves Fiona and Fiona returns his feelings. Lord Farquaad obviously doesn't agree and tries to stop them but is foiled in his attempt by a dragon. After this event Shrek and Fiona kiss and Fiona is finally turned into her true self, to her surprise she becomes an ogre. She thinks off herself as hideous at first but then Shrek tells her she looks beautiful and they live happily ever after.