Solution: A Masterclass in Ascendant

A perfect masterclass in the power of Case: Ascendant.

Opening

First, we have an obvious lane peak as a result of lasers.

But from here, we’re really in a pickle. All we’ve got are a bunch of $2$-clues, no opposing clues, and not much interaction between them.

But as we’ll find out, the secret is all in the interaction between them.

Blockade

The first lane we might want to look at is the top row, since we have the most constraints here.

A good question to consider here is, “Must the head cell be the $4$-skyscraper?”

Well, we could also put the $4$ after the peak, and everything would be fine, so we can’t say this for sure yet.

For now, we’ll pencil in $[34]$ and $[123]$ via Case: Leap of Faith.

Now let’s focus on the bottom row, and consider where the lane peak can go. The 2nd column is taken, so that leaves just the last 3 columns.

Now Case: Blockade comes in. Consider these two adjacent $2$-clue columns. In these lanes, if the $5$ is in the tail cell, then the $4$ must be in the head cell.

But we’ve already deduced the candidates for those head cells to be $[123]$, so a $4$ can’t go there. So contrapositively, the $5$ cannot go there.

And that leaves only this spot for the $5$. Nice!

Now we can actually use Blockade, putting a $4$ here.

And now we can determine with certainty that original head cell must be a $4$, since the right column now has the $4$ consumed.