The solution is

>! FREE RIDDLE BOOK AT LIBRARY.

To find it,

>! take the last letter before every punctuation mark.

I thought of this because of the unusual words "Fiji" and "plea", which were clearly significant -

>! "Fiji" might have been included because of the J, but "plea" was clearly included because of the final A, and then it becomes clear that "Fiji" was included because of the final I.

Also in the title of the email,

>! "deck stair" ~ "dexter", which means right - as in the right-hand end of a word or clause.