There is more than one thing going on here. The team are working without Booth for the fourth time it seems until Brennan manages to involve him.
First they have to identify the cadavers from a plane crash and find that an unaccounted for passenger was on the flight.
Then there are unrelated bone fragments.These introduce the theme of missing parents and the search for them which links in with Brennan's family problems. This theme seems to take precedence although the search for the identity of the fragments eliminates one possibility and introduces a murder which is ultimately solved.
Another theme is that of the team working behind Dr Goodman's back. Loved the scene between Goodman and Hodgins where the boss comes down real heavy then walks away grinning.
The inner child comes out again in both Hodgins and Zack with their woodchipper experiment. Mind you it was Booth who identified the machine - think he has an inner child too.
Excellent interplay between Brennan and Booth and also between Booth and Zack.