Cheerleading coach Sue Sylvester ( Jane Lynch ) becomes principal of William McKinley High School , and glee club members Mercedes Jones ( Amber Riley ) and Kurt Hummel ( Chris Colfer ) experience tension in their friendship .
Cheerleading coach Sue Sylvester ( Jane Lynch ) becomes principal of William McKingley High School , and glee club members Mercedes Jones ( Amber Riley ) and Kurt Hummel ( Chris Colfer ) start to feel stress in their growing friendship .