plotting a matrix like multiple ascii files

I have a dataset with multiple ascii files with same x axis and different y axis. These ascii files corresponds to different time steps in the measurement. I want to plot them on one plot such that I see the change of data with time. I am using following set of commands

fh = load('horizontal_scan_energy_normalized.dat');

where 'horizontal_scan_energy_normalized.dat' is a matrix with all the ascii files, I created it using origin. Where the first column is the x-axis of each ascii file. Then I call

y = fh(:,1);

and define x as a vector with values for time steps and then

imagesc(x,y,fh)

however the y-axis appear not as the one for single ascii files, rather uniformly distributed. How can I solve this

[KSSV]

Why imagesc? You should use plot. Have a look on plot.

[Mamuna Anwar]

I used it because length of y and x is not same x is 1x20 double and y is 1x449 double. how can I use plot for this data?