Treat it as no trick and prepare yourself accordingly

but keep your secret information to yourself.

If they ask about he secret information, you can say "it is difficult to describ in short period of time. if you hire me, i will make the full information/story/package etc available to you." etc. don't show any sign of doubts in your mind that it might be a trick.

Job is difficult to get now, and make 120% effort to fight for it. This might be a great opportunity. You never know. And good luck!