Heading Style Misapplied to Body Text

Hi, 

I'm editing a novel manuscript.  Somehow. the author applied the same heading used for the chapter numbering to the last line of text of Chapter 28, so that that short line and the Chapter 29 heading are ... linked? If I try to set the heading for the line of text to normal in the Style pane, the chapter 29 heading goes to "normal," too.  If I try to apply the heading style to the chapter heading, the line of text gets that style, too. 

Chapter 29 has of course disappeared from the Navigation Pane in all this. 

Any advice is very welcome.