under wraps (adj.)

• abstruse
• arcane
• blind
• buried
• cabalistic
• censored
• classified
• close
• closed
• clouded
• concealed
• covered
• covert
• cryptic
• dark
• enigmatic
• esoteric
• hermetic
• hidden
• hush-hush
• incommunicado
• latent
• mysterious
• obscure
• occult
• recondite
• restricted
• secluded
• secret
• sequestered
• smothered
• stifled
• suppressed
• ulterior
• underground
• undisclosed
• unknown
• unrevealed
• unspoken
• untellable
• untold
• unutterable
• unuttered