Generate a histogram of pass angles, set the fill to be blue, then overlay a line graph for pass.lengths vs pass.angles, set the line colour to be red.

I am trying to solve this question: Generate a histogram of pass angles, set the fill to be blue, then overlay a line graph for pass.lengths vs pass.angles, set the line colour to be red.
I put in the code but I cannot figure out how to make the line colour red. The following code gives me a black line. What should I add to generate a red line?

ggplot(passing, aes(pass.angle))+
geom_histogram(fill="blue1")+
geom_line(aes(x=pass.angle, y=pass.length))

In geom_histogram, you set the fill to be blue1. The equivalent argument in geom_line would be to set the color to be red outside of the aes() function.