California Code, Code of Civil Procedure - CCP § 116.390

(a) If a defendant has a claim against a plaintiff that exceeds the jurisdictional limits stated in Sections 116.220, 116.221, and 116.231, and the claim relates to the contract, transaction, matter, or event which is the subject of the plaintiff's claim, the defendant may commence an action against the plaintiff in a court of competent jurisdiction and request the small claims court to transfer the small claims action to that court.

(b) The defendant may make the request by filing with the small claims court in which the plaintiff commenced the action, at or before the time set for the hearing of that action, a declaration stating the facts concerning the defendant's action against the plaintiff with a true copy of the complaint so filed by the defendant against the plaintiff. The defendant shall cause a copy of the declaration and complaint to be personally delivered to the plaintiff at or before the time set for the hearing of the small claims action.

(c) In ruling on a motion to transfer, the small claims court may do any of the following: (1) render judgment on the small claims case prior to the transfer; (2) not render judgment and transfer the small claims case; (3) refuse to transfer the small claims case on the grounds that the ends of justice would not be served. If the small claims action is transferred prior to judgment, both actions shall be tried together in the transferee court.

(d) When the small claims court orders the action transferred, it shall transmit all files and papers to the transferee court.

(e) The plaintiff in the small claims action shall not be required to pay to the clerk of the transferee court any transmittal, appearance, or filing fee unless the plaintiff appears in the transferee court, in which event the plaintiff shall be required to pay the filing fee and any other fee required of a defendant in the transferee court. However, if the transferee court rules against the plaintiff in the action filed in that court, the court may award to the defendant in that action the costs incurred as a consequence of the transfer, including attorney's fees and filing fees.