Ruka's 30 copies of doujinshi has sold out in just an hour. Nagi realises that people are only buying her doujinshi for the photobook of Maria that she advertised. Realising defeat, she runs away in disappointment only for Hayate to catch up with her and let her read Ruka's manga to see the difference. She finally understood that the difference was because Ruka was earnest in wanting to draw a doujinshi that would reach out to the people.
Hayate recalls a quote from Santa at the start of the series where "the one who laughs last are the earnest and the honest".
The 1st scene in Chapter 268 is finally explained here when Nagi storms outside because she realised that Ruka has "defeated" her by selling out all her doujinshi. (The same scene can be seen in the end)