Simplify the following text for a Grade 10 native English-speaking person.
Original: Backlash ( 2004 ) was a professional wrestling pay-per-view event produced by World Wrestling Entertainment ( WWE ) , which took place on April 18 , 2004 at the Rexall Place in Edmonton , Alberta , Canada .
Simplified: Backlash ( 2004 ) was the sixth annual Backlash professional wrestling pay-per-view ( PPV ) event produced by World Wrestling Entertainment ( WWE ) . It took place on April 18 , 2004 at the Rexall Place in Edmonton , Alberta and was a Raw brand-exclusive event .