What does "heroes required - apply within" mean?

Question

A film review reads:

An accepted conceit in Hollywood, and amongst world leaders engaged with reality, is that our time on Earth is at risk of running out. In other words, "heroes required - apply within". One of the most intriguing heroes of recent year - on the fictional side of things at least - is Matthew McConaughey's Cooper in Christopher Nolan's 2014 smash Interstellar.

What does "heroes required - apply within" mean here? I feel like it is used in a whimsical tone but I do not exactly know what it is referring to. In particular, dictionaries suggest that "apply within" means

to ask about something [inside some place]

How is it applied in this context? Aside from that, I am also not quite sure about the meaning of "conceit" here. The definition of it is:

an ingenious or fanciful comparison or metaphor.

Is the author suggesting that "The Earth is at a risk of running out" is an ingenious idea in Hollywood? I am not quite sure about that because it seems to be a very common idea.

As a side note, I haven't watched the Interstellar before, if that matters. Thanks in advance.

Answer 1

"Apply within" is a term used in advertisements for job vacancies when they are displayed at the business premises where the vacancy exists. It literally means that, to apply for the job, you go inside the premises where the sign is displayed and ask. This is in contrast with other kinds of advertisements that might invite you to write or call someone to make an application - you actually go within to apply. A common variation is "enquire within", which has a broader use such as just obtaining information rather than applying for something. In your example, it is being used lightheartedly. The idea of applying for a job by walking into a workplace and asking is one of the most informal ways to get a job, so it works well as a metaphor for inviting someone to do something of their own volition.

A "conceit" is a poetical or literary device that makes a comparison between something in fiction, and in real life. In classical literature, metaphysical conceits could be quite complex - for example, drawing comparisons between spiritual and physical things. Here it is less lofty - it is just saying that ideas used in fictional movies are meant to draw comparisons to real life.

Overall, the message of the review is that the movie Interstellar uses the conceit that the world is ending, and that ordinary people must 'step up' to be heroes, and that this is inviting people to do the same in real life.