Undercurrent
Undercurrent is a flow of water below the surface:

In an ocean, a subsurface current, a water current which flows beneath and usually independently of surface currents.
In a river, a subsurface current (see whitewater)It may also refer to:

Books
Undercurrent (newspaper), a Canadian newspaper
Undercurrent (manga), a 2005 manga by Tetsuya Toyoda
The Undercurrent (novel), by Robert Grant (writer)

Film and TV
The Undercurrent (1919 film), a 1919 American drama film directed by Wilfrid North
Undercurrent (1946 film), a film directed by Vincente Minnelli, starring Katharine Hepburn
Undercurrent, an alternate title for the 1956 Japanese film Night River
Undercurrent, a 1999 film starring Lorenzo Lamas
Undercurrent (2010 film), an Icelandic film, starring Gísli Örn Garðarsson
Undercurrent: The Disappearance of Kim Wall, a 2022 HBO documentary on the Murder of Kim Wall, by Erin Lee Carr
"Undercurrent", a 1976 episode of The Onedin Line

Music
Undercurrent (Kenny Drew album), a 1960 album by pianist Kenny Drew
Undercurrent (Bill Evans and Jim Hall album), a 1962 album by pianist Bill Evans and guitarist Jim Hall
Undercurrent (Sarah Jarosz album), a 2016 album by Sarah Jarosz
Undercurrent (Matisyahu album), a 2017 album by Matisyahu
The Undercurrent (album), a 2008 album by French band Scarve
UnderCurrent Entertainment, a record label whom hip hop artist Abhi the Nomad is signed to, among others

See also
Undercurrents (disambiguation)