The I chord goes the the IV chord and then to the V. It resolves back to the I.
You play with these expectations to build structures for verses, bridges, and choruses, but no song I know subverts the whole business like this one.
"Magical Music Box" seems to have three distinct sections. The band first come barrelling in with a I-IV progression and the continuation of this is how the verse begins, riding that fifth scale degree in the melody and ready to plunge gloriously into some inevitable cadence. By the end of the second line, things are already going wrong.
The second line instead just flops down onto the tonic note. It doesn't rhyme.
Neither do the third and fourth lines. Then, there's a fifth line, "I wonder what will come," first scale degree up to the second as the chord changes from I to IV. The second scale degree is not a part of the IV chord.
So, after an irregular set of five lines with no rhyming they pick their odd spot to move up to the V chord. Nevertheless, they ride it out like that cadence is coming
It isn't, though. It's back to the IV chord to start the chorus (0:42). This time, it's IV-V, so I guess it's a cadence when it goes from there to I, but they're landing on the downbeat of a consequent line, not an antecedent line. It's not the right time for it. Plus, that first line was only one bar long, not two like the one that follows it.
Second line of the chorus starts on that I chord and moves to IV, two bars like the I-IV in the verse. Back in the third line to I-IV again; are we going to have a rhyme here? Nah, instead they extend it two bars by going to the V chord, the same dominant prolongation we had in the fifth line of the verse. Again, it feels like an odd time for this event to occur.
No cadence even after the long-held V chord, it instead repeats the IV-V but with a different melody and this time for the full two bars. Still no cadence after this, it repeats instead that first line, but they treat it differently this time. They treat the two beats on the IV chord as a measure of 2/4 and then hold that V chord for two bars of 4/4.
You can't make this stuff up! (Well, of course, the genius that wrote this song did.)