Clue: Energy-packed story adapted for silent type in bed? (6)
Answer: OYSTER
Explanation: Definition: silent type in bed?

**E** (energy) *packed into* ***(story) **[anag:*adapted*}
 
*As well as being the creature found in an (oyster) bed, "oyster" is also a word used to describe a tight-lipped person you can rely on to keep a secret, hence a* "silent type".