Filmen handler om zombien.

In Norwegian, the definite article is usually attached to the end of the noun.

• en film = a film / a movie
• filmen = the film / the movie

So filmen is the definite singular form of film.

For the same reason: zombien is the definite singular form.

• en zombie = a zombie
• zombien = the zombie

Because the noun already ends in -e, the definite form is written zombien. That is the normal way to form the definite singular here.

Handle om is a fixed expression meaning to be about or to concern.

So:

• Filmen handler om zombien = The movie is about the zombie

This is important because handle on its own can have other meanings in Norwegian, but handle om specifically means be about.

Not here. Even though handler looks like English handles, the meaning is different in this sentence.

In Filmen handler om zombien, handler om means:

• is about
• deals with
• concerns

So do not translate it word-for-word as English handles.

Not normally. Norwegian usually uses handler om for is about.

So:

• natural: Filmen handler om zombien
• unnatural or non-idiomatic: Filmen er om zombien

If you want to say what a movie is about, handle om is the standard choice.

Because the sentence is talking about a specific movie and a specific zombie.

• filmen = the movie
• zombien = the zombie

If you made one or both nouns indefinite, the meaning would change:

• En film handler om en zombie = A movie is about a zombie
• Filmen handler om en zombie = The movie is about a zombie
• Filmen handler om zombien = The movie is about the zombie

So the definite forms show that both are already known or specific in the context.

Handler is the present tense of å handle.

A very common Norwegian pattern is:

• infinitive: å handle
• present tense: handler

So Filmen handler om zombien is in the present tense, just like English The movie is about the zombie.

That would mean The movie is about a zombie, not the zombie.

Compare:

• Filmen handler om zombien = about one specific zombie
• Filmen handler om en zombie = about some zombie, not necessarily one already identified

This is the same definite/indefinite contrast that English has with the vs a.

A simple English-friendly approximation is:

FIL-men HAN-dler om zom-BI-en

A few notes:

• filmen has two clear syllables: FIL-men
• handler is also two syllables: HAN-dler
• zombien is usually heard as zom-BI-en

The stress is strongest on FIL-, HAN-, and -BI-.

Yes, in everyday Norwegian film commonly means movie.

So filmen here is best understood as:

• the movie
• or the film

Both are fine in English.