The Best Episodes Written By Karen Maser

The BAU investigates when several young men and women are victims of disfiguring acid attacks. Also, Dr. Reid begins to settle into his new surroundings.

Director: Rob Bailey

Writer: Karen Maser

The team heads to Yakima, Washington when the remains of a dozen people are found along a creek bed.

Director: Christoph Schrewe

Writer: Karen Maser

Several women go missing in Virginia and the BAU must figure out what they all have in common in order to find them.

Director: Aisha Tyler

Writer: Karen Maser

The BAU welcomes back Emily Prentiss as they are called upon to investigate the disappearance of three women

Director: Alec Smight

Writer: Karen Maser

When bodies are discovered in public places throughout Boston, the BAU investigates whether a taxi or ride-share service the victims used before their deaths could lead the team to the UnSub.

Director: Tawnia McKiernan

Writer: Karen Maser

The BAU is called to investigate a series of deaths in Virginia suspected by the Center for Disease Control to be caused by bio-terrorism; Garcia visits her stepbrother to take care of a family issue.

Director: Diana Valentine

Writer: Karen Maser

When is it time to go out on a limb? Armand Assante guest stars as a patient who makes Sam an offer she might not be able to refuse. Luka must calm Abby’s baby-related fears after an incident at the hospital places everyone at risk. Kerry makes a difficult choice, and Neela joins a support group.

Director: Lesli Linka Glatter

Writer: Karen Maser

Kovac and Gates treat a girl who appears to have been assaulted. When the police are no help with Ames, Kovac decides to confront the problem himself; Morris and other doctors work on a patient with an ice pick in his ear. Meanwhile, Ray tries to keep his new relationship a secret and Pratt can't fully deal when his half-brother officially comes out. Also, a new male nurse arrives.

Director: Laura Innes

Writer: Karen Maser

Moretti begins to make his presence felt, as he implements changes in the way patients are seen. The ER staff differ on how procedure when a patient comes in with a bullet in him needed as evidence. Neela finds herself the object of more attention that she wants, or needs. Abby had passport woes, and struggles with the changes being made. Pratt and Morris find themselves forced to defend their actions, Hope prepares for a new mission, and Gates finds himself labeled the reject in his new assignment.

Director: Richard Thorpe

Writer: Karen Maser

Kovac is in Chicago looking for hospice-care work. Neela's aorta surgery has caused an infection in her patient. Abby treats a teen who has been beaten up. Brenner continues to cause problems for the ER staff.

Director: Andrew Bernstein

Writer: Karen Maser

Morris is named the new chief resident, which makes nobody really happy, except Morris. Meanwhile Luka and Sam are having communication problems, Carter gets a promotion Susan really wanted and Ray finds out a 14-year old who always comes in for free drugs has been raped.

Director: Ernest R. Dickerson

Writer: Karen Maser

Morris faces a complicated case involving a young girl hit while riding her bicycle. Gates finds it very difficult to let go of his feelings for Sam. Neela becomes quite flustered when Brenner returns from Australia.

Director: Richard Thorpe

Writer: Karen Maser

The BAU is called to New York when several casualties of a brutal nature are reported in Central Park.

Director: Christoph Schrewe

Writer: Karen Maser

It's Sam's birthday, but she finds it hard to be away from her son Alex. Meanwhile, Sam meets a photographer taking pictures of a terminal patient and she gives Sam a new perspective on life. Dubenko's new surgical intern unsettles Neela during a trauma; Gates is shadowed by a new and nerdy intern and later must tell Sarah the truth that he may be her biological father. Also, Morris and Hope annoy Kovac and Abby when they try to help with their wedding preparations.

Director: Stephen Cragg

Writer: Karen Maser

It's time for changes at the ER when Anspaugh makes an unpopular decision. Abby has old demons to fight with, which distance her from friends and family. Even Luka seems to be at a loss to help Abby. Love is in the air when a secret romance blooms between two doctors.

Director: Paul McCrane

Writer: Karen Maser

It's Halloween night, and the interns continue to be paired with the residents. Gates's teaching methods with Daria, and her responses, belittle Sam. A school fight results in a stabbing and a nose that won't stop bleeding, with Brenner treating the victims and being deeply affected by the truth behind their confrontation. The staff, especially Neela, are enthusiastic about a surprise visitor. Gates gets locked in a maintenance area with a quiet young boy.

Director: Christopher Chulack

Writer: Karen Maser

When brides-to-be in Savannah are killed on the eve of their nuptials, the BAU suspects a jilted UnSub is at work.

Director: Joe Mantegna

Writer: Karen Maser

Supergirl finds an opportunity to escape from the Phantom Zone but it comes with some dangerous strings attached. Meanwhile, Lena joins the Super Friends on a mission but finds she disagrees with their plan of action against the Phantoms and wonders if she is truly ready to be a part of the team.

Director: Alysse Leite-Rogers

Writer: Karen Maser

Lena is uncertain about using her magical abilities to help Supergirl retrieve the second totem from Nyxly. William struggles to write a story on the Super Friends that makes both the heroes and Andrea happy. Meanwhile, Kelly is thrilled Esme has found a new home, but things go awry and the little girl's future is put in danger.

Director: Simon Burnett

Writer: Karen Maser

Kelly meets Joey, a young orphaned alien boy, who is acting out in foster care because he fears there is something wrong with his brother Orlando, who is incarcerated. Kelly asks Kara to help her investigate and they stumble upon abuse at the prison. Meanwhile, Nyxly crashes one of Nia's dreams and asks her for help.

Director: Shannon Kohli

Writer: Karen Maser

Supergirl is determined to keep everyone safe from Lex and Nyxly so she doubles down on patrol, especially as Alex and Kelly's bachelorette party is coming up. Alex is torn between duty and finally allowing herself the time to enjoy her new family. Brainy receives heartbreaking news, and William clashes with Andrea over her recent coverage of Lex.

Director: David McWhirter

Writer: Karen Maser