At the beginning of your draw step, Maralen triggers, causing you to lose three life, then search your library for a card and put it into your hand.
During each opponent's draw step, Maralen triggers, causing them to lose three life, then causing you to search their library for a card and exile it.
You may play cards exiled this way due to Opposition Agent.

Lock

Players can't draw cards

Exile a card of your choice from an opponent's library on each opponent's turn and you may cast that card

Maralen of the Mornsong

Opposition Agent

Maralen prevents players from drawing cards. The ability to search libraries will be rendered moot for opponents due to Stranglehold.

Opponents can't search libraries

Stranglehold

Maralen prevents players from drawing, but allows tutors, Mindlock Orb prevents players from tutoring

Players can't search libraries

Mindlock Orb

At the beginning of your upkeep, Clearwater Goblet triggers, causing you to gain at least three life.
At the beginning of your draw step, Maralen triggers, causing you to lose three life, then search your library for Nexus of Fate and put it into your hand.
Cast Nexus of Fate by paying {5}{U}{U}, causing you to take an extra turn after this one and shuflle Nexus of Fate into your library.
Repeat each turn.

Infinite turns

Nexus of Fate

Clearwater Goblet

At the beginning of your upkeep, Maralen triggers, causing you to lose 3 life and search your library for Timestream Navigator and put it into your hand.
Cast Timestream Navigator by paying {1}{U}.
If you don't have the city's blessing, Timestream Navigator gives you the city's blessing.
Activate Timestream Navigator by paying {2}{U}{U}, tapping and putting it on the bottom of your library, causing you to take an extra turn after this one.
Gain at least 3 life.
Repeat each turn.

Skip your draw steps

Timestream Navigator

Akroma's Memorial

At the beginning of your upkeep, Clearwater Goblet triggers, causing you to gain at least three life.
At the beginning of your draw step, Maralen triggers, causing you to lose three life, then search your library for Beacon of Tomorrows and put it into your hand.
Cast Beacon of Tomorrows by paying {6}{U}{U}, causing you to take an extra turn after this one and shuflle Beacon of Tomorrows into your library.
Repeat each turn.

Combos with "Maralen of the Mornsong"