Curiosity House volume 1
Harper, an imprint of HarperCollins Publishers
"Orphans Philippa, Sam, Thomas, and Max must find out who stole a valuable artifact in order to save to save their home, Dumfrey's Dime Museum of Freaks, Oddities, and Wonders"--
Curiosity House volume 2
Four orphans are shocked when their beloved friend, sculptor Siegfried Eckleberger, is murdered. As they investigate, they find clues that his death may be tied to the murder of a rich New York heiress as well as to their own past.
Curiosity House volume 3
The extraordinary orphans Sam, Philippa, Thomas, and Max have just started to recover from their capture and subsequent escape from the evil Nicholas Rattigan. But the children's lives don't stay quiet for long. A slew of bank robberies is terrorizing the city. And when General Farnum, the ringmaster of the museum's now immensely popular flea circus, is charged with murder, the search for the real killer uncovers a plot much bigger than any individual...