It's rare to see Isabelle Mercier disappear from the World Series. If it happens, it's generally her time to catch some R&R at the Bellagio. She generally reappears within a couple of days, tanned and clutching a cup of coffee. When she vanished a couple of weeks ago, though, she didn't come back in short order.

Isabelle's mother was recently diagnosed with breast cancer. Doctors performed a lumpectomy while the Series played out in Vegas. Mercier rushed home to be by her mother's side. Whether No Mercy would make it back to Vegas in time to play in her favorite event was unclear. Nothing was clear--whether Mercier would see Vegas again this summer, how her mother would come out of the surgery, or what would come next.

"She was so strong," Mercier said.

Isabelle's mother is a buoyant woman. It's not uncommon to see her alongside Isabelle as she strides through casino hallways. It's clear, mother and daughter are best friends. It seemed impossible Isabelle would be able to play in any tournament, let alone the $50,000 HORSE event.

But, Isabelle's mom recovered from her surgery quickly. What's more, she wanted her daughter to play in this important event. A few nights ago, Isabelle's mom entered a HORSE tournament on PokerStars and made the final table.

"She practiced for me," Isabelle said with a small smile.

And so, Isabelle arrived here looking determined as she sat down in the $50,000 HORSE event. Her mother was strong, Isabelle said, and that gave No Mercy strength as well.

The PokerStars family is no stranger to struggles with cancer. By now, few people are unaware of Gavin Griffin's crusade against the disease. His girlfriend is a survivor and they both work to raise money to search for a cure.

Today was supposed to be an important day. Isabelle was waiting to learn from doctors if the cancer had spread any further than the lump. If it had, there was no doubting where Isabelle's mind, and likely her luggage would be.

She finished Day 1 of the HORSE event with a good stack and waited for the call this morning. Her mother eventually told her the appointment had been moved until Monday.

"I didn't believe her," Isabelle said.

See, Monday is the day after the final table of the $50,000 HORSE event. A suspicious person, say a female poker player named Isabelle, might think Isabelle's mom was sheltering her from bad news. Isabelle only believed after her mother handed over the doctor's name and phone number.

Now, Isabelle sits at table #17 with a look so determined, you'd think she was already at the final table. She has a better than average chip-stack and an eye to go deep. Her mother, though, is never far from her mind.

"I am playing this for her, 100%," she said.

For more from Isabelle on this event, check out the video blog below.