'Grey's Anatomy': Helen Karev Makes Surprise Return

Grey's Anatomy's record-breaking episode brought many surprises, but the surprise arrival of Alex's mom, Helen, takes the cake.

During "We Didn't Start the Fire," Alex (Justin Chambers) and Jo (Camilla Luddington) are shocked when Helen Karev (Lindsay Wagner) arrives at the hospital for a surprise visit.

Given her history of mental health problems, Jo is concerned that her mother-in-law might have been motivated to travel to Seattle because of a psychotic break, though she seems to be fine for most of the episode.

Alex catches up with his wife and mother at Jackson's (Jesse Williams) big celebration for Catherine (Debbie Allen) and he initially plans to take Helen home and figure out what's going on later, but she disappears into the party while he and Jo discuss what to do next.

He later finds Helen talking to DeLuca and she insists that she is fine, even though her arrival in Seattle is extremely out of character for her.

She then reveals to her son that she knitted scarves of every color for him to choose is favorite as a wedding present, but starts to feel insecure. Alex makes her feel better by picking a green scarf for himself and a blue one for his wife.

As the party goes on, Alex tries to get in contact with Helen's doctor, but is unable to reach him. Jo comforts him by saying she thinks Helen seems fine, and they might just have to wait for an update in the morning.

"My mom comes to visit and I have to worry it's a sign she's going to split from reality," Alex says. "I want to trust it so much that she's fine."

Things take a concerning turn later when Alex tells Helen he was surprised by her visit, but she begins to act erratically after she smells smoke. Alex tries to talk her down, fearing she might be having an episode just as Jackson is about to give his toast at the party, but smoke starts to come out of the kitchen and he seems overjoyed that Helen did not imagine it.

After evacuating, Helen and Meredith (Ellen Pompeo) have a sweet moment together when they finally meet.

"Meredith, you're Alex's best friend," Helen says.

Meredith smiles and responds:"I am, and he's mine."

Near the end of the episode, Jo and Alex settle in to go to sleep and seem happy about their unexpected visitor, but give one concerned look at Helen fearing the worst is yet to come.

Fans of the series will remember Alex struggled with taking care of his mentally ill mother throughout his childhood. Back in Season 14, he and Jo visited Helen in Iowa and found out her schizophrenia had been under control and she was working as a librarian.

Will Helen's visit take a tragic turn in future episodes? Grey's Anatomy airs Thursdays at 8 p.m. ET on ABC.