<P> During the fourth - season episode `` Now You See Me , Now You Do n't '' , CeCe is revealed to be Red Coat . In the sixth - season episode `` Game Over , Charles '' , Drake unmasked herself as Big `` A '' , and revealed that she was born male and underwent gender reassignment surgery . In the following episode `` Of Late I Think of Rosewood '' , it is shown that Charlotte spent the subsequent five years at the Welby State Psychiatric Hospital . Charlotte is eventually released from Welby after the Liars ( minus Aria ) lie under oath and testify in favor of her release as a favor to Alison . However , Charlotte is murdered by an unknown assailant merely hours after leaving Welby . Her death fueled the rise of a new `` A '' , using the alias A.D. , who was severely adamant on avenging Charlotte 's homicide . During the sixth - season finale `` Hush , Hush , Sweet Liars '' , the Liars discover that Jessica DiLaurentis has an identical twin sister , Mary Drake , a former patient at Radley Sanitarium who is Charlotte 's biological mother . In `` The DArkest Knight '' , Mary is revealed to be Spencer Hastings ' biological mother , thus making her Charlotte 's maternal half - sister . During `` Farewell , My Lovely '' , Mona confesses to killing Charlotte after finding out that her mental health had n't improved and her intentions were to harm the Liars again . In `` Till Death Do Us Part '' , the elusive A.D. is revealed to be Alex Drake , Spencer 's identical twin sister . Alex believed the Liars knew who orchestrated Charlotte 's murder and was also set on physically replacing Spencer due to envying the upbringing she was able to have . </P>
<P> During the fourth - season episode `` Now You See Me , Now You Do n't '' , CeCe is revealed to be Red Coat . In the sixth - season episode `` Game Over , Charles '' , Drake unmasked herself as Big `` A '' , and revealed that she was born male and underwent gender reassignment surgery . In the following episode `` Of Late I Think of Rosewood '' , it is shown that Charlotte spent the subsequent five years at the Welby State Psychiatric Hospital . Charlotte is eventually released from Welby after the Liars ( minus Aria ) lie under oath and testify in favor of her release as a favor to Alison . However , Charlotte is murdered by an unknown assailant merely hours after leaving Welby . Her death fueled the rise of a new `` A '' , using the alias A.D. , who was severely adamant on avenging Charlotte 's homicide . During the sixth - season finale `` Hush , Hush , Sweet Liars '' , the Liars discover that Jessica DiLaurentis has an identical twin sister , Mary Drake , a former patient at Radley Sanitarium who is Charlotte 's biological mother . In `` The DArkest Knight '' , Mary is revealed to be Spencer Hastings ' biological mother , thus making her Charlotte 's maternal half - sister . During `` Farewell , My Lovely '' , Mona confesses to killing Charlotte after finding out that her mental health had n't improved and her intentions were to harm the Liars again . In `` Till Death Do Us Part '' , the elusive A.D. is revealed to be Alex Drake , Spencer 's identical twin sister . Alex believed the Liars knew who orchestrated Charlotte 's murder and was also set on physically replacing Spencer due to envying the upbringing she was able to have . </P>
when do the liars find out that charles is cece
when do the liars find out that charles is cece
In the sixth - season episode `` Game Over , Charles ''
In the sixth - season episode `` Game Over , Charles ''