What does the cryptic crossword clue "Dreams hide a secret when you look behind the surface (5)" mean?

The definition is "Dreams". The wordplay uses a hidden word. Hidden in "dreams hIDE A Secret when you look behind the surface" The answer is IDEAS.

Dreams hide a secret when you look behind the surface (5)

Independent Cryptic #11724 | 13 Across | 2024-05-08 flower