Fiona and David is a happy couple,but unfortunately,they separate in an accident on their journey.
—— separate 虽然表示“分开”,但是却有婚姻结束的含义,应该改为 stray from each other.
David is searching all over the place for her.
—— 改为 David is searching where they have been for her.(找遍了他们曾汲去过的地方)
When Fiona wakes up,she find out she lost her memory in nowhere.
—— 此处与上文衔接不够紧密,应该补充过渡段并修改如下：
During she stays apart,Fiona falls asleep where she is staying alone.When she wakes up,she finds out she her wallet is nowhere with her.
Accidentally,she meets Jay,a farmer who falls in love with her after they live together.
—— 与上文的时空无法衔接,因此也得修改.
Accidentally,she meets Jay,a farmer,and she has to live with him for short time.Finally,he falls in love with her.
All good things will come to an end,David found Fiona at last,but he is so distress because she can't recognize him.
Until he shows their love token,and she recalls everything.At last,they continue their journey.
—— until 引导都是状语从句,但是却没有主句,致使句子不通,应该改为：
She doesn't recall anything until he shows his love just as in the past.