Parents at the Cardinal Gibbons School vowed Thursday to fight its planned closing.

Less than 24 hours after the Archdiocese of Baltimore announced it would shut the high school down at the end of the school year, parents had scheduled a rally on the Wilkens Avenue campus for 2 p.m. Saturday and were planning to launch a fundraising campaign to pay a debt of $1.3 million.

"We know this will be difficult, but we have to try," said Chris Schene, whose son, Gregory is a junior at the school. The Schenes have also opened their home to Samuel Smith, who transferred from a school in England to finish his last two years of high school at Cardinal Gibbons.

"You can't find the camaraderie we have in a bigger school," Schene said. "My son knows everyone in every grade."

Cardinal Gibbons is the only high school among the 13 schools that the archdiocese is planning to close in June. The closings are part of a reorganization that Archbishop Edwin F. O'Brien has described as necessary in the face of declining student populations and rising costs.

While enrollment at Cardinal Gibbons has dropped in recent years to fewer than 400 boys, parents said the school had assured them as late as Dec. 31 that it had met its enrollment figures and was solvent. They said they were surprised to read of the debt in a letter sent to them this week.

"All we want is the truth," said Janine Fratantuono, who has two sons in the school. "Just give us the real reason."

The decision to close the school and the reaction among families mirrors those at Towson Catholic High School last summer. After church officials announced in July that they would not reopen the school in September, parents and students held rallies, raised money and filed a lawsuit seeking to reverse the decision. They were unsuccessful.

"I do feel for these kids, faculty and the parents who have sacrificed to send their children to Catholic schools," said Towson Catholic parent Lois Windsor, who helped to lead the effort there. "I hope and pray that these kids will find a school that they can call home and those who have the luck of keeping their schools open will be kind and try to understand what other the families will be going through. We did not keep our school open but at least we went down with class, which was the TC style."

St. Agnes Hospital has long been said to have an interest in expanding onto the Cardinal Gibbons property. On Thursday, rumors circulated that the hospital and the archdiocese were negotiating or had completed a deal.

Archdiocesan officials said Thursday that there was no foundation for the rumors. Bishop Dennis Madden said there had been no discussions between the archdiocese and the hospital about the school property.

"We think these boys were sold out," Schene said. "The Archdiocese will deny it for years, but St. Agnes will eventually have this property."

O'Brien has promised every student displaced by the closings a spot in another school. Schene said she is not comforted.

"My son deserves to graduate as a Crusader," she said. "His school ring says 'Crusader 2011.' Families sacrifice a lot to send their kids to this school."