Butterworth filter without the 's' option

I have to use the 'butter' function WITHOUT the 's' option, and plot the response to an input, in time domain. In the documentaion, I only see how to do frequency domain plots (when not using the 's' option). I know how to do this by using the 'butter' function WITH the 's' option, and then using the 'c2d' function, but I have to also do it the other way, and I can't find any documentation or videos that show how. Can anyone help? Thank you.