How should I understand 〜ぬ時は?


[![enter image description
here](https://i.stack.imgur.com/Vb1jR.png)](https://i.stack.imgur.com/Vb1jR.png)

I'm confused on this picture. The question is, my teacher told me that

> 来ない時は(約束した日時または時間)
>
> 分かっておるであろうな(あなたはどうなるのか分かっているはずだ)

But I don't understand how can it change into this? I understand about the
translated version from my teacher now but when I was trying on translation on
the first time it went like this.

> "The time that you doesn't come, You're understand?" It's weird right?

But from my teacher, I can understand it now.

Except I don't know how to change `来ぬ時間` into `約束した時間`.

Is it some kind of grammar?

Especially `分かっておるであろうな` into `あなたはどうなるのか分かっているはずだ`

I can understand that わかっておる can translate into わかっている but It's followed by
であろうな.

What does it mean, and how can it turn into `あなたはどうなるのか分かっているはずだ`?




It's a good question. :)

> 来ない時は(約束した日時または時間)  
>  分かっておるであろうな(あなたはどうなるのか分かっているはずだ)

来ない時は is actually equivalent to a **_condition/premise_** ; **もし** 来なければ
**どうなるか**. どうなるか is only _implied_ , and continues to the question,
分かっているだろうな, which is to remind (you) what follows if (you) don't come, saying
it in an intimidating tone like an old sage.

