Die Gutenachtgeschichte ist heute so spannend, dass sogar die Babysitterin bis zum Ende zuhört.

German very often combines nouns into a single compound word. Here:

• gute Nacht = good night
• Geschichte = story

Together they form Gutenachtgeschichte = bedtime story / good-night story.

A useful rule: in German compounds, the last part is the main noun. So Geschichte is the core word, and that affects the gender too.

Also, like all nouns in German, Gutenachtgeschichte is capitalized.

Because the main part of the compound is Geschichte, and Geschichte is feminine: die Geschichte.

Since the last element decides the gender of the whole compound, you get:

• die Geschichte
• die Gutenachtgeschichte

So even though the word is long, you can often find the gender by looking at the final noun.

So ... dass is a very common German pattern meaning so ... that.

In this sentence:

• so spannend = so exciting
• dass ... zuhört = that ... listens

So the structure is:

• Die Gutenachtgeschichte ist heute so spannend, dass ...
• The bedtime story is so exciting today that ...

This construction shows a result: the story is exciting to such a degree that even the babysitter keeps listening.

Because dass introduces a subordinate clause, and in German subordinate clauses are separated by a comma.

So:

• main clause: Die Gutenachtgeschichte ist heute so spannend
• subordinate clause: dass sogar die Babysitterin bis zum Ende zuhört

This comma is required in standard German.

Because the part starting with dass is a subordinate clause, and in German subordinate clauses the conjugated verb usually goes to the end.

So instead of a main-clause order like:

• Die Babysitterin hört zu

you get:

• ..., dass die Babysitterin zuhört

That final verb position is one of the most important German word-order rules.

The verb is zuhören = to listen. It is a separable verb.

In a normal main clause, separable verbs split:

• Die Babysitterin hört zu.

But in an infinitive or in a subordinate clause, they usually stay together:

• ..., dass die Babysitterin zuhört
• zuzuhören

So both forms come from the same verb, zuhören.

Often zuhören can take a dative object if you say who is being listened to:

• Sie hört dem Kind zu. = She listens to the child.

But the object can also be left out if it is obvious or not important:

• Sie hört bis zum Ende zu.

In your sentence, the focus is on the fact that the babysitter keeps listening all the way through, so the object is simply omitted.

Bis zum Ende means until the end or all the way to the end.

Zum is a contraction of:

• zu dem → zum

So literally:

• bis zum Ende = until to-the end

You do not translate it word for word into natural English, but the German expression is very common.

Because spannend comes after ist and works as a predicate adjective.

Predicate adjectives in German are not inflected:

• Die Geschichte ist spannend.
• Das Buch ist interessant.

You would use an ending only when the adjective comes before a noun:

• eine spannende Geschichte

So:

• die Geschichte ist spannend ✅
• die Geschichte ist spannende ❌

Sogar means even.

It adds emphasis and shows that something is surprising. Here, the surprising part is that even the babysitter listens until the end.

Its position matters: it comes right before the thing being emphasized:

• sogar die Babysitterin = even the babysitter

If you move sogar, the emphasis can change.

Yes, German adverbs are somewhat flexible, and heute could appear in different positions depending on emphasis.

Here:

• Die Gutenachtgeschichte ist heute so spannend ...

This is a very natural placement.

You could also hear:

• Heute ist die Gutenachtgeschichte so spannend, dass ...

That puts stronger emphasis on today.

So the sentence you have is normal, but German word order often allows small shifts to change focus.

Here die Babysitterin is the subject of the subordinate clause, so it is in the nominative case.

Also, Babysitterin is feminine, so the nominative singular article is die:

• die Babysitterin = the babysitter (female)

If it were dative, you might see der Babysitterin, but that is not the role it has here. In this sentence, she is the one doing the listening.