We can assume it's not a TV recording of the show, nor the original filming tapes with actors, etc. but only a manuscript, otherwise the work would have many copies lying around (tv station, etc.). So the show never got filmed nor streamed and the original manuscript got burnt.
Theoretically Bob owns the copyright, but how does he prove it? To be able to fully enforce a copyright you usually have to register your work in the corresponding administration to prove 2 things: a) the work is yours, and b) you had the idea at time X (before person B at a later time).
Also if you have any proof of the original work with an official timestamp (post or email over a public service), that would be enouh, but in this case there is nothing, just a work hidden in a storage locker.
Now to be able to enforce in future the copyright, he would at least have to remember from scratch the main points in the TV Show, write them down again and register those with the US Copyright office. Otherwise Bob will face a lengthy trial where he will have to defend his claim that he had the original idea and somebody "stole" it from him, also taking into account, that the accused could argue he came by himself to a similar idea at an earlier point in time than Bob. That would be pretty costly for Bob with very few chances to win, except he would have proof that the accused got the idea from him (voice recording, email traffic of aknowledgment, etc.).
Nevertheless if the accused did register his work properly before the claim and Bob did not even have the slightest register of his idea (not even an email to himself over a public server as gmail where he describes his idea), it will very very difficult for bob to defend his claim.
To register a claim to copyright with the U.S. Copyright Office, the
claimant must: (1) submit a properly completed application; (2) pay a
nonrefundable fee; and (3) deposit the required number of copies of
the works to be registered.
So it depends on the country. I know that in switzerland for example specially in early times, an (e)mail to yourself over a public (e)mail service (which cannot falsify dates), is enough to make a claim, even if the counterparty registers the work for himself at a later date. This would be a valid proof. Then the second step would be to compare the works to judge if they are similar enough to infringe copyright.
hope that helps