### Clue: 21 run off in pursuit of junk shop thief (4,2,3,6)
### Answer: SHIP OF THE DESERT 
 ### Explanation: Definition: 21
 DESERT(to run off/to abandon someone or something) **placed after**(in pursuit of) **anagram of**(junk) SHOP THIEF.
Defn: Answer to 21 across.