There's a trick about taking us in (4)
I believe the answer is:
ruse
'there's a trick' is the definition.
(I've seen this before)
'about taking us in' is the wordplay.
I cannot quite understand how this works, but
'us' is found in the answer.
'about' could be 're' (regarding) and 're' is present in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ruse that I've seen before include "Sure to be a plot" , "Trick, stratagem" , "Subterfuge" , "Cunning plan" , "trick played" .)