Why is this sentence translating in such a weird way? Is it a mistake, or is this some sort of German idiom?
Got me too! From what I see of its use on German web sites it does appear to be an idiom.
in answer to your question, yes its a german expression "handeln von" means to be about or to deal it.
What's tripping you up? Is it the "er" or the "wovon"? I think that it's common to use "er" or "sie" instead of "es" for an "it" that you know the gender of. (Though I'd love a clear explanation on when these are and aren't used.) As for "wovon", German often uses these "where from"/"where to" constructions, as in "Wohin gehst du?" for "Where are you going?" They even use "worüber" to mean "what about", as in "Worüber sollen wir sprechen?" ("What should we speak about?").
It does fell pretty shakespearian :-)