Warning: Contains SPOILERS for His Dark Materials season 2, episode 4, “Tower of the Angels.”

His Dark Materials answered a long-standing question about why daemons can’t touch other people when, in season 2, episode 4, “Tower of the Angels,” Lyra’s daemon Pan shared an intimate and taboo touch with Will Parry. Daemons are a common sight in Lyra’s world, but they’re more than just constant companions. As author Phillip Pullman explains in the His Dark Materials trilogy, daemons are a manifestation of the soul, and often reflect the emotions and impulses of their human counterparts.

In His Dark Materials seasons 1 and 2, daemons are seen touching other daemons the same way people touch other people. Although daemons appear less frequently on screen, Pullman’s novels make it clear that social contact between daemons mirrors humanity’s social norms. The daemons of close friends might greet each other with close contact, while the daemons of strangers will be more hesitant to touch. In conflicts, daemons may even physically fight. For example, Mrs. Coulter’s orangutan daemon is seen subduing the daemons of others in the books and the series.

Related: His Dark Materials Season 2 Fixes The Show’s Daemon Problem

Conversely, contact between a person and a daemon that is not their own is exceedingly rare. As representations of a person’s inner self, daemons are hypersensitive to the touches of others. Such interaction typically occurs only in situations of heightened emotion — during a fight to the death or behind the closed doors of a bedroom. In “Tower of the Angels,” Pan is touched twice, once by a stranger and once by Lyra’s friend Will. The two interactions are wildly different, showing how Lyra’s thoughts and feelings influence Pantalaimon’s behavior. Likewise, Lyra’s reactions to the contact show how she feels about Will and the boy she fights.

Lyra’s daemon is first touched by someone else in His Dark Materials season 1, episode 6, “The Daemon-Cages,” when she’s taken to be permanently severed from her daemon. As Lyra tries to escape, a member of the General Oblation Board seizes Pan with both hands, resulting in Lyra’s immediate collapse. Unlike fights between daemons, the attack on Pan by a human leaves Lyra reeling and immobile. It’s difficult to portray on television, but the novels describe the touch as creating a strong sense of repulsion — it’s not just a physical violation, but a metaphysical violation as well. Touching someone else’s daemon is akin to touching their soul.

In The Golden Compass, Pullman writes of the moment that “It was as if an alien hand had reached right inside where no hand had a right to be, and wrenched at something deep and precious. (Lyra) felt faint, dizzy, sick, disgusted, limp with shock.” Lyra has a similar reaction when Pan is kicked away during a fight in “Tower of the Angels.” The contact is brief, but Lyra immediately drops to the ground, seemingly hit in the same spot where Pan was struck, and is down for the rest of the brawl.

Unlike Pan’s contact with others in His Dark Materials, the daemon’s exchange of touch with Will Parry is voluntary and gentle. In fact, it’s Pan who reaches out to touch Will in “Tower of the Angels,” rather than the other way around.  Pan reaches out to Will because he feels at ease with the boy and wants to comfort him in a time of crisis. When Will asks if he’s done something wrong by touching Pan, the daemon responds, “It was me Will. I wanted to.” Lyra is on the same page, saying, “He wanted to help.“.

Related: Who Is John Parry: Andrew Scott’s His Dark Materials Character Explained

The touch foreshadows Lyra and Will’s blossoming romantic relationship in Pullman’s novels. Lyra’s reaction to her daemon’s contact with Will is not violent or painful, but shocked and perhaps aroused. In the final book of the series, The Amber Spyglass, Will touches Pan with love, resulting in a “pleasure like joy” within Lyra. It’s less evident in HBO’s TV adaptation, but some readers interpret the settling of daemons as a metaphor for growing up, and more specifically, of sexual awakening. The taboo surrounding contact with daemons reinforces the idea, with unwilling contact likened to sexual assault, and willing contact likened to making love.

More: His Dark Materials Season 2: Everything Seen In Lyra’s Dust Vision