MyComicBrowser plugin issues

https://borkweb.com/story/wordpress-plugin-mycomic-browser

I have the plugin installed and the entries are created in my database. I can create posts that do drop in and populate the database. The problem is getting the data back out. I’ve added the line of code referenced on the website and added it to a page template.

<?php if($comic=mycomic_is_comic($id)) mycomic_navigator($comic,$id); ?>

Now when I navigate to the page with this code applied I get an error message.

WordPress database error: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ” at line 1] SELECT comic FROM wp_comic WHERE post_id=;

I understand how to look at the structure of mysql databases but I’m not to good with writing the code to get data in/out so I’m a little stumped. Any help would be greatly appreciated! Thanks in advance!