"Criminal Minds" character Spencer Reid is fighting to prove his innocence but the next episode promises to be suspense-filled as time is not on his side.

Fans will recall that the BAU agent was set up by Mr Scratch to make it look like he committed a murder that in reality he didn't commit.

In the upcoming episode called "Assistance Is Futile," Reid is having a tough time in prison and things are about to get worse for him as he was denied bail in the last episode and faces being transferred to the Millburn Correctional Facility, which houses some nasty criminals that he helped to put away. 

His life could be seriously in danger if these inmates decide to take their chance for revenge. 

It must feel like a lonely time for Reid but he at least has one friend in the form of ex-FBI agent Calvin Shaw.  And of course the BAU team are fighting for him too.  

The trailer for the next episode sees a desperate Reid weighing up his options as he knows time is running out to prove his innocence.

JJ tries his best to encourage him by reminding him that the BAU stands by him, but the trailer takes a sinister turn when it switches to inamtes at the correctional facility threatening Reid in his own prison cell.  They call him out as a snitch before launching an attack on him. 

It certainly promises to be a gripping episode as the trailer gives no clue as to the outcome of the confrontation and whether the BAU is able to save their man before it's too late.

There's more exciting news in store for the next episode, as Academy Award winner Tatum O'Neal is reportedly guest starring as a mother who knows something that might prove valuable to the BAU.

According to the synopsis, the mother comes forward with some important information that might help their ongoing investigation into a creepy unsub, dubbed the bone crusher.

Tune into the next episode of "Criminal Minds" season 12 over on CBS on Wednesday, March 15, at 9 p.m. EST.