It seems like the film should stop right there.
Sigrid is freaked out, leaves the house and plans to never see Christian again.
Sigrid comes to think that the Frank situation isnt a dealbreaker and continues dating Christian.

Frank in ‘Good Boy’ is not actually a dog.
The two decide to go on a weekend away to Christians secluded country home.
There, things take a sickening turn.
By the time Sigrid decides she doesnt want to deal with Frank, it is too late.

Overall,Good Boyis pretty freaky.

Sigrid meets Frank the “dog”.

Christian (Gard Løkke) warns Sigrid that Frank must be treated like any other dog.