(CNN) -- One mother cherishes a photo her son snapped while riding horses together. Another loves biking with her son along the rivers around Philadelphia. A third clings to her last visit with her daughter in Syria.
The three have formed a bond through adversity, and this week, they met up in New York with a message for Iranian President Mahmoud Ahmadinejad: Give us our children.
As Mother's Day nears, the three moms are heading back home -- to Minnesota, Pennsylvania and California -- without an answer and with their children, who the world knows as "the hikers," still jailed in Iran.
But looking back over the past nine months, the mothers do have something to hold on to: their bond with each other.
They have formed a unique friendship centered around freeing their children. They call each other often and e-mail. Sometimes, like this week, they meet in person to push their fight.
"At this point, what we want is our kids to be released immediately. We want action on this," Nora Shourd said. "These are our children, and there's nothing quite as anguishing as thinking about your kids in prison in a country so far away and being unable to help them."
The news cycle moves on, but for these moms, the cause never fades. It consumes their lives. Nobody can fully understand their anguish, they say, and that's why their bond is so tight. Jobs have been put on the back burner; some of their other children have postponed graduate studies to help free their siblings.
"The other person gets it right away," Shourd said of the mothers' roller-coaster emotions. "That is a very strong kind of thing that's helped us in this situation."
"Everyone one of us is being touched in a very bottom-line way," Cindy Hickey added.
The three applied for visas six months ago to see their children. They're still awaiting word.
"We'd like to get there ... and do what mothers do: give them some nurturing," Hickey said. "It's very frustrating for us that it seems we're thrown in the middle of these two countries and their disharmony."
Hickey's son, Shane Bauer, 27; his girlfriend, Sarah Shourd, 31; and Josh Fattal, 27, were arrested in July for illegally entering Iran from Iraq's Kurdistan region. The three friends are being held in Tehran's notorious Evin Prison, where political prisoners were kept during the 1979 revolution.
The three Americans first bonded around 2002, when Shane Bauer and Josh Fattal first lived together at the University of California-Berkeley. Shane and Sarah Shourd soon began dating.
The avid hikers strayed across an unmarked border into Iran during a hiking trip in a largely peaceful area of Iraq, the families say. They have not been formally charged, although Tehran has said they will face trial.
A host of powerful dignitaries, from U.S. Secretary of State Hillary Clinton to Archbishop Desmond Tutu, have called for their release.
Ahmadinejad traveled to New York this week for the opening of a month-long conference on nuclear nonproliferation at the United Nations.
In a speech before the U.N., he didn't reference the hikers. But he was quoted in the New York Times as saying he would like to see them freed, along with seven Iranians who he says are imprisoned in the U.S.
"We are working to release all of the prisoners," Ahmadinejad said.
"We would have loved him to bring the kids home with him, but that was not the case," Fattal said.
The three jailed Americans have had little contact with the outside world. They made a brief phone call home March 9 and have access to a few letters and messages sent by relatives, friends and supporters.
The Swiss ambassador to Iran met with the detainees last month and said Shane and Sarah are in poor health and are considering a hunger strike.
The United States, which has not had diplomatic relations with Iran since 1979, has relied on Switzerland to appeal directly for the hikers' release.
The mothers' emotions are torn as they head toward their first Mother's Day with their children incarcerated. They hope to remain strong for their other children, but they know Sunday will bring a lot of pain.
"This is going to be an especially tough day," Hickey said. "There's going to be an empty space because I won't hear from my son."
She and Shane love riding horseback together in Minnesota. Two years ago, he gave her a photograph on Mother's Day. It was a photo he snapped of her during one of their excursions. She proudly displays it in her living room.
"It reminds me every day of where I need to go to seek quiet, so I can remain strong," she said.
That's where she'll probably be on Sunday: trotting on a horse, minus her favorite partner, the young man with a "gentle spirit and compassion for all human beings."
Fattal isn't sure what she'll do Sunday. Her oldest son, Alex, has been the primary spokesman for the families and has kept the fight going to make sure Josh and his friends in captivity aren't forgotten.
Maybe she'll take a bike ride along the Delaware River, one of Josh's favorite places to ride. But it's not where she wants to be. She'd like to be anywhere as long as it's with her missing son.
"He sees humor and can really bounce with very diverse situations," she said. "I hold that very close and tight to me."
Shourd says she often thinks of her last trip to see her daughter, Sarah, in Damascus, Syria, where she was living with Shane.
"Those are my immediate memories," she said, "seeing how their life was there and how they learned how to live in a country like that and get close to the people there."
All three mothers cling to the hope that Ahmadinejad -- who is a father -- will show compassion and clear them to travel.
"Perhaps, we can be in the air later this week and we will see our kids on Mother's Day," Fattal said. "We don't make plans more than 24 hours in advance. We hold every day precious and hope for good news."
Shane and Josh are being held together, while Sarah is alone in a cell. They are allowed to meet twice a day for brief periods but are isolated from other prisoners.
"Their emotional stability is advanced by being together," Shourd said, "though they are in such a situation of tremendous adversity."
The three moms can relate to such a close-knit friendship. They're hoping somebody in the regime will read this piece and, as Shourd puts it, "step aside from whatever politics are out there and be compassionate and show our kids the compassion we know they have."
"They just need to be released," she said. "Although they're extraordinary people to us, they're just ordinary Americans."