This article is from the 2006 series of SMBZ and is no longer canon.
The two first met during the events of Sonic CD, where Dr. Eggman used her as bait when Sonic attempted to disrupt his schemes on the Little Planet to acquire the Time Stones. Since then, she developed a strong interest in Sonic and follows him on several of his adventures, trying to help however she can.
She was only seen briefly in SMBZ, in a flashback showing Sonic's friends getting killed by Mecha Sonic. It was shown that she was most likely beaten to death.