The case of the buried clock

After catching his son-in-law embezzling, wealthy banker Vincent Blane is shocked when the younger man is murdered and Blane's daughter is accused, prompting him to call in Perry Mason for her defense.
A buried clock appears, disappears, and re-appears.
It is set to sidereal time -- the time used by the stars as opposed to the Earth. The book explains this.
But who did it? And why? And when? And where?
So much to discover -- so little time when two defendants are being tried and neither will talk to Perry. Not even the one who is his client.