Learn Turkish: Romandaki kurgu biraz sıradan. - The plot in the novel is a bit ordinary.

Romandaki has the -ki suffix attached to the locative -da. Why use this instead of a possessive like Romanın kurgusu (the novel's plot)?

Romanın kurgusu (a noun compound) frames the plot as an inherent structural part of the book. Romandaki kurgu (the plot in the novel) treats the novel as a location where the plot is found. At a B2 level, you will notice native speakers often prefer -daki when offering a critique of what they experienced inside the work, though both are grammatically correct and interchangeable here.

The word sıradan (ordinary) looks like it has the ablative case suffix -dan (from). Is that how it was formed?

Yes! Sıra means row, line, or order. Adding the ablative -dan originally meant something came from the row (like a generic item off an assembly line). Over time, sıradan became a fixed adjective meaning run-of-the-mill or ordinary.

This lesson focuses on double negation. How would we apply that nuance here to say 'It is not that the plot isn't ordinary' (meaning it actually is)?

Because this sentence uses an adjective (sıradan) instead of a finite verb, you create double negation by repeating the negative word: Romandaki kurgu sıradan değil değil. This gives the exact B2-level nuance of conceding a point ('It isn't not ordinary'). If you wanted to use a finite verb to match the lesson's main formula, you could use gelmek (to seem): Kurgu bana sıradan gelmiyor değil (The plot doesn't not seem ordinary to me).