BOSTON -- Despite being ordered to return to work, Quincy teachers plan to walk the picket lines again Monday, which means a second day off for thousands of public school students.

The teachers union and city representatives were scheduled to meet with a state mediator Sunday afternoon. It is the second negotiating session since the teachers voted to strike last week. During a six-hour meeting on Saturday, the teachers made a new offer, but no new agreement was reached.

According to the Patriot Ledger of Quincy, it's the first time in 20 years that teachers in the city have voted to strike. The sticking point appeared to be how much teachers are willing to pay for their health insurance.

The union took the strike vote even though it's illegal for public employees in Massachusetts to walk off the job.

The teachers plan to vote on whether to return to the classroom at 11 a.m. Monday. Union officials told NewsCenter 5 that they hope to present a tentative agreement to its members by then.