Plot a line of maximum frequencies over spectrogram

I know this has been explored before, and I have been trying things from earlier posts. I plot a spectrogram. Then, for some reason, even though "hold on" is called before I plot the line, the spectrogram is erased and the line plots on a white background. I got it to work just fine using the example in Matlab Docs under the spectrogram section.

{As a side note, and perhaps relevant: I also noticed that changing the parameters of Fs and N had a similar result when Fs and N were almost the same. (The relationship changed for different sized N, but generally speaking, if Fs was above 90% to 99% of N, then the red line (max values at each frequency bin) would not plot at all). }

I have made sure that the z-value for the red line is above the z-values on the spectrogram, and also that the zlimit allows for these values.

if true
  % 
spectrogram(y,100,80,100:2500,Fs,'yaxis')
view(-77,72)
shading interp
colorbar off
view(2)
[s,f2,t,p] = spectrogram(y,100,80,100:2500,Fs);%t=1.294
[q,nd] = max(10*log10(p));
hold on
plot3(t,nd,q*.2,'r','linewidth',4)
xlim([0 1.294])
ylim([100 2500])
zlim([-100 10])
end

If anybody can help I would sure appreciate it! Thanks, Noah