CASCADE, Wis.(WHBL) - A Plymouth man was seriously injured late Monday morning when his pickup truck left the road and slammed into a tree north of the village of Cascade.  The Sheriff’s Department said 58 year old Robert Demmers was headed north on Cedar Lane Road when he went through the stop sign at the T-intersection with County U and slammed into the tree.  Demmers, who said his brakes failed, was flighted to Froedert in Milwaukee.  He was cited for drunk driving.