((Uh... thanks?))

In general: These seem pretty vague, in that there doesn't seem to be a lot to critique, because they're just the sort of one sentence summary that you can find on the back of any old book in a bookstore. And, of course, since they are vague, a lot of their quality would depend on how intricate the actual plot is, how well the ideas are handled (storm of cliches, or snappy deconstructions?), character depth, et cetera. 

1. Generally speaking I distrust the phrase "unlocks the secret of his/her past" on principle that it has been done to death and back. But that might just be me. Further: Where is "this place," why is she there, why is it important, why is the treasure box there and why is it important/how does it unlock the secrets of her past, who are her real parents and why was she separated from them, et cetera. The best way to build a plot is to ask questions about the exciting vague summaries that you make up. So do that. 

2. This one seems pretty similar to number one, replacing the chest with Mrs. Sears and real parents with long-lost siblings, so you may want to consider trying to, I don't know, combine them somehow? Perhaps one of the real parents (the mother, I suppose) is one of the siblings and Mrs. Sears is the puppetmaster behind the seperation of the daughter and the discovery of the trunk?

3. Now this one seems quite interesting, although the Oxford Book would have to be pretty intense in order for the plot to come off as you want it to (dramatic, instead of trite). How exactly does a book being published lead to its thief taking over the world? It would have to be a pretty important book, so when you do answer that question you'll want to do it carefully. (You do not, naturally, have to answer me if you don't want to, but certainly you'll want to think the answer through prior to execution). 

Of course, if you could find a way to do all three at once, that would be exponentially more awesome than just one at a time. So that's something to bear in mind, if you can pull it off without it becoming cheesy or contrived.

I would certainly love to hear more. 

Sorry if these seemed pretty bad... they were ust short story ideas that I wanted to bounce off you all but never got anywhere. So, instead, comment on these plots, they're for my novels.

The first, foremost, novel I'm writing is about a girl who wants to be an author when she grows up. Intertwined are chapters about this other friend, Fira, and her secret, which eventually will have something to do with the main character winning a story contest (probably with the story of Fira's secret.) I think the story will be called Fira's Secret although it's not very... original... cliche, if you will.

My other idea was about this girl, Elise, whose mother has died, and now she has to live with her cousins, who are rather...less then nice. Then Elise meets this friend who claims she knew Elise's mom, but, who we find out later, actually is her mom, who came to meet Elise as a way to "come to terms" (excuse all of my cliches, but its the easiest way to describe) with her mom's death.

Let me know what you think.

P.S. TNO, my comment about you was a compliment. Sorry if it seemed otherwise.