'The Bachelor' recap: Clayton discovers 1 of the women might be playing him

Clayton Echard continued his journey to find love with the 22 remaining women on Monday's episode of "The Bachelor," but one of them has a secret that could force him to do something no other Bachelor has done before.

The season’s first group date featured celebrity guest Hilary Duff, who enlisted 10 of the ladies to throw a dream Beverly Hills birthday party for one lucky young girl and her guests. Cassidy, however, was more interested in spending time with Clayton than the kids.

While the bold strategy didn't sit well with the other women, Clayton was impressed with her tenacity and rewarded her with the date rose.

Unfortunately, Cassidy's unrelenting pursuit of Clayton, along with her cockiness, led her to make a potentially fatal mistake when she privately told Sierra that she had a guy back home that she'd been "hooking up with on and off for a while." In fact, the two had video chatted just as she was on her way to tape the show and made plans to hook up again after she was done.

Later, at the pre-rose ceremony cocktail party, Sierra used her time alone with Clayton to spill the beans about Cassidy, warning him that she's not the person he thought she was.

That led Clayton to ask host Jesse Palmer a question that could change Cassidy's future and lead to a Bachelor first: "Has anyone has ever taken back a rose before?"

The episode ended with a cliffhanger, as we await Jesse's response.

Meanwhile, another drama was brewing after Shanae -- who, during another group date, tried stealing a page from Cassidy's playbook by calling Elizabeth "fake" to Clayton. That lead to tension between the two ladies and raised red flags regarding both of them.

Afterwards, it was Sarah who took home the date rose.

Elsewhere, Susie landed a one-on-one date with Clayton that included a scenic helicopter ride, sipping champagne on a yacht, a surprise musical performance by Canadian country singer Amanda Jordan and a date rose.

Here are the other women still in the running:

Cassidy, 26, an executive recruiter from Los Angeles, California

Eliza, 25, a marketing manager from Berlin, Germany

Elizabeth, 32, a real estate advisor from Highlands Ranch, Colorado

Ency, 28, a sales manager from Burbank, California

Gabby, 30, an ICU nurse from Denver, Colorado

Genevive, 26, a bartender from Los Angeles, California

Hunter, 28, a human resources specialist from Charlotte, North Carolina

Jill, 26, an architectural historian from Scituate, Rhode Island

Kate, 32, a real estate agent from Lake Hollywood, California

Kira, 32, a physician from Philadelphia, Pennsylvania

Lyndsey W., 28 an industrial sale representative from Houston, Texas

Mara, 32, an entrepreneur from Collingswood, New Jersey

Marlena, 30, a former Olympian from Gainesville, Florida

Melina, 27, a personal trainer from West Hollywood, California

Rachel, 25, a flight instructor from Clermont, Florida

Sarah, 23, a wealth management advisor from New York City, New York

Serene, 26, an elementary school teacher from Oklahoma City, Ohio

Shanae, 29, a recruiter from Sycamore, Ohio

Sierra, 26, a yoga instructor from Dallas, Texas

Susie, 28, a wedding videographer from Virginia Beach, Virginia

Teddi, 24, a surgical unit nurse from Highland, California

Tessa, 26, a human resources specialist from Brooklyn, New York

"The Bachelor" returns Jan. 24 at 8 p.m. ET on ABC.