I think the sentence is unnatural or has an error, because there is no main verb in it, I've reported it but, please if I'm wrong can anyone tell me the reason or explain the sentence to me!
There's nothing wrong with it, actually. Måste can be used like that to express "have to go".
Det är sent, jag måste hem = It's late, I have to go home.
German has the same grammatical feature.
Ich muss jetzt in die Schule - I have to go to school now
Ich muss jetzt ins Bett - I have to go to bed now
I guess it's because it's kind of obvious, so the verb 'to go' isn't necessary.