Breakdown of Handlingen var det mest överraskande som hade hänt.
vara
to be
ha
to have
hända
to happen
det
the (with ett-words)
Questions & Answers about Handlingen var det mest överraskande som hade hänt.
Why do we use mest here instead of adding an ending like -aste to mean "most"?
The word for "surprising" is överraskande. Because it ends in -ande (it is a verb turned into an adjective, similar to English words ending in "-ing"), we cannot add normal adjective endings to it. Instead, we must use mer for "more" and mest for "most".
Where is the word for "thing" in the Swedish sentence?
It is built into det. When you want to say "the [adjective] thing" in Swedish, you often do not need a separate word for "thing". You just use the neuter article det plus the adjective, so det mest överraskande means "the most surprising [thing]".
Since we are using the neuter word det, why doesn't överraskande get an extra -t at the end?
Normally, an adjective matching a neuter word like det gets a -t added to the end. But adjectives that end in -ande or -ende are exceptions. They are completely inflexible and never change their spelling for gender or plural forms.
Does handlingen have something to do with shopping here?
Not in this sentence! While the verb att handla commonly means "to shop", it can also mean "to be about". Because of this, the noun en handling is the word used for the plot or storyline of a book or movie.