Use data in an array for 'Plot' command

I need to draw a shape using the 'Plot' command, the data is stored in an array called 'shape'. This is my attempt so far:

                  for i=1:1:length(shape(j,4,i))-1
                      plot([shape(j,4,i) shape(j,4,i+1)],[shape(j,5,i) shape(j,5,i+1)],'k');
                      hold on;
                  end
                  plot([shape(j,4,i))(length(shape(j,4,i)) shape(j,4,i)(1)],[shape(j,5,i)(length(shape(j,5,i))) shape(j,5,i)(1)],'k');
                  end

I receive this error: "Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters."

Is this the correct format to use to call data from an array because I cannot see any problems with the brackets?

Thank you