In the distant future, Captain Malcolm ‘Mal’ Reynolds is a renegade former brown-coat Sargent now turned smuggler/rogue who is the commander of a small spacecraft with a loyal hand-picked crew made up of first mate Zoe Warren; pilot Hoban ‘Wash’ Washburn; gung-ho grunt Jayne Cobb; engineer Kaylee Frye; fugitives Doctor Simon Tam and his psychic sister River, where they travel the far reaches of space in search of food, money, and anything to live off on.
The first major problem is that this is one sentence, which would be fine if it had any structure. We’ll need to break it down into logical units, form some clauses, and put it back together.
The first clause is about Captain Reynolds background. There’s nothing technically wrong with “renegade former brown-coat Sergeant”, it’s just awkward, and anyone who actually needs to read the description won’t know what a “brown-coat” is. The rest of the description is simply mangled. First, this is no place for a slash. In my opinion, that device is reserved for titles, bulleted lists, and sportswriting. Second, to make the clause work you’d need to hyphenate everything from “renegade” to “rogue”—that’s a lot of hyphens.
Here we move from a discussion of who Cpt. Reynolds is to what he does. If “who is the” were replaced by “and” the sentence would read much better, but side from that, and the comma needed after “loyal”, the phrase is good. The crew section would be fine as well if the semicolons (which require complete clauses on both sides) were commas , but is uncomfortable.
The last clause should be a new sentence, which would eliminate the need for the awkward “where” that begins the clause.
Here’s the ReWrite:
“Set in the distant future, Captain Malcolm ‘Mal’ Reynolds – formerly a Sergeant for a crushed resistance army, now a smuggler – commands a small spacecraft with a loyal, hand-picked crew: first mate Zoe Warren, pilot Hoban ‘Wash’ Washburn, gung-ho grunt Jayne Cobb, engineer Kaylee Frye, and fugitives Doctor Simon Tam and his psychic sister, River. They travel the far reaches of space in search of food, money, and answers.”