<P> Chloe and Clark patch their relationship in the season three episode `` Whisper '' , after Clark discovers that she has been helping Lionel . When Chloe stops her investigation , Lionel has her fired from the Daily Planet , and also fires her father from his job at LuthorCorp . In season three 's `` Forsaken '' , Chloe decides to assist Lex Luthor ( Michael Rosenbaum ) , Lionel 's son , with getting Lionel arrested for the murder of Lex ' grandparents ; Chloe 's hope is to get out from under Lionel 's control . In the season three finale , the F.B.I. place Chloe and her father in a safe - house until Lionel 's trial ; unfortunately , the safe - house explodes once Chloe and her father enter and they are presumed dead . Chloe 's cousin , Lois Lane ( Erica Durance ) , comes to Smallville to investigate Chloe 's death in the fourth season premiere . In season four 's `` Gone '' , Clark and Lois team - up and discover that Lex 's security team found the explosives in the safe - house , pulled Chloe and her father to safety before they detonated , and that he has been hiding her ever since . After Chloe 's testimony in the same episode , Lionel is convicted of murder and sentenced to life imprisonment . In the season four episode `` Pariah '' , Chloe discovers Clark 's secret when Alicia Baker ( Sarah Carter ) , Clark 's girlfriend , decides that it needs to be exposed to the world in order for him to feel more comfortable about who he really is . Alicia hopes that Chloe will write a story exposing Clark , but Chloe decides that Clark kept his secret for a reason and decides not to write the story . </P>
<P> Chloe and Clark patch their relationship in the season three episode `` Whisper '' , after Clark discovers that she has been helping Lionel . When Chloe stops her investigation , Lionel has her fired from the Daily Planet , and also fires her father from his job at LuthorCorp . In season three 's `` Forsaken '' , Chloe decides to assist Lex Luthor ( Michael Rosenbaum ) , Lionel 's son , with getting Lionel arrested for the murder of Lex ' grandparents ; Chloe 's hope is to get out from under Lionel 's control . In the season three finale , the F.B.I. place Chloe and her father in a safe - house until Lionel 's trial ; unfortunately , the safe - house explodes once Chloe and her father enter and they are presumed dead . Chloe 's cousin , Lois Lane ( Erica Durance ) , comes to Smallville to investigate Chloe 's death in the fourth season premiere . In season four 's `` Gone '' , Clark and Lois team - up and discover that Lex 's security team found the explosives in the safe - house , pulled Chloe and her father to safety before they detonated , and that he has been hiding her ever since . After Chloe 's testimony in the same episode , Lionel is convicted of murder and sentenced to life imprisonment . In the season four episode `` Pariah '' , Chloe discovers Clark 's secret when Alicia Baker ( Sarah Carter ) , Clark 's girlfriend , decides that it needs to be exposed to the world in order for him to feel more comfortable about who he really is . Alicia hopes that Chloe will write a story exposing Clark , but Chloe decides that Clark kept his secret for a reason and decides not to write the story . </P>
when does chloe sullivan find out about clark
when does chloe sullivan find out about clark
In the season four episode `` Pariah ''
In the season four episode `` Pariah ''