It all started with an email typo. Entering a client's email address last week, a contractor accidentally swapped @gs.com for @gmail.com — so instead of sending to a Goldman Sachs employee, the message went to a random stranger.

Normally, that would just be an embarrassment, but this particular email included private client data, and Goldman Sachs is willing to move heaven and earth to get it back. According to a new report from Reuters, the battle has taken the Wall Street firm to the New York State Supreme Court, pleading with Google to delete the email to prevent a "needless and massive privacy violation," in the company's words.

It's an unprecedented demand — effectively asserting the right to unsend an email if it can be established that the email was sent in error — but Google says it's willing to comply if Goldman can get a court order to that effect. Still, it's not clear exactly what legal reasoning the bank would appeal to. Thus far, the company has relied on emergency relief claims, arguing that Google "faces little more than the minor inconvenience of intercepting a single email — an email that was indisputably sent in error," balanced against Goldman's potentially disastrous data breach.

Update, 7/3 9:48AM EST: Reuters is reporting that Google has complied with its request and blocked access to the email in question. According to Google, the user had not accessed the account since June 23rd, so there's no reason to believe the client data was compromised. Google performed the block without being compelled by the court, so any questions of legal precedent remain unresolved.